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mysql-server/sql/item_cmpfunc.cc
Ho Sy Tan 4a107fd10e 2025-03-05 14:31:08
2025-03-05 14:31:37 +07:00

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/* Copyright (c) 2000, 2024, Oracle and/or its affiliates.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License, version 2.0,
as published by the Free Software Foundation.
This program is designed to work with certain software (including
but not limited to OpenSSL) that is licensed under separate terms,
as designated in a particular file or component or in included license
documentation. The authors of MySQL hereby grant you an additional
permission to link the program and your derivative works with the
separately licensed software that they have either included with
the program or referenced in the documentation.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License, version 2.0, for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
/**
@file sql/item_cmpfunc.cc
@brief
This file defines all Items that compare values (e.g. >=, ==, LIKE, etc.)
*/
#include "sql/item_cmpfunc.h"
#include <algorithm>
#include <array>
#include <cassert>
#include <climits>
#include <cmath>
#include <cstdint>
#include <cstring>
#include <type_traits>
#include <utility>
#include "decimal.h"
#include "field_types.h"
#include "mf_wcomp.h" // wild_one, wild_many
#include "my_alloc.h"
#include "my_bitmap.h"
#include "my_dbug.h"
#include "my_sqlcommand.h"
#include "my_sys.h"
#include "mysql/strings/dtoa.h"
#include "mysql/strings/m_ctype.h"
#include "mysql/udf_registration_types.h"
#include "mysql_com.h"
#include "mysql_time.h"
#include "mysqld_error.h"
#include "sql-common/json_dom.h" // Json_scalar_holder
#include "sql/aggregate_check.h" // Distinct_check
#include "sql/check_stack.h"
#include "sql/current_thd.h" // current_thd
#include "sql/derror.h" // ER_THD
#include "sql/error_handler.h"
#include "sql/field.h"
#include "sql/histograms/histogram.h"
#include "sql/item_func.h"
#include "sql/item_json_func.h" // json_value, get_json_atom_wrapper
#include "sql/item_subselect.h" // Item_subselect
#include "sql/item_sum.h" // Item_sum_hybrid
#include "sql/item_timefunc.h" // Item_typecast_date
#include "sql/join_optimizer/bit_utils.h"
#include "sql/key.h"
#include "sql/mysqld.h" // log_10
#include "sql/nested_join.h"
#include "sql/opt_trace.h" // Opt_trace_object
#include "sql/opt_trace_context.h"
#include "sql/parse_tree_helpers.h" // PT_item_list
#include "sql/parse_tree_node_base.h" // Parse_context
#include "sql/query_options.h"
#include "sql/sql_array.h"
#include "sql/sql_base.h"
#include "sql/sql_bitmap.h"
#include "sql/sql_class.h" // THD
#include "sql/sql_const.h"
#include "sql/sql_error.h"
#include "sql/sql_executor.h"
#include "sql/sql_lex.h"
#include "sql/sql_opt_exec_shared.h"
#include "sql/sql_optimizer.h" // JOIN
#include "sql/sql_select.h"
#include "sql/sql_time.h" // str_to_datetime
#include "sql/system_variables.h"
#include "sql/thd_raii.h"
#include "string_with_len.h"
using std::max;
using std::min;
static const enum_walk walk_options =
enum_walk::PREFIX | enum_walk::POSTFIX | enum_walk::SUBQUERY;
static bool convert_constant_item(THD *, Item_field *, Item **, bool *);
static longlong get_year_value(THD *thd, Item ***item_arg, Item **cache_arg,
const Item *warn_item, bool *is_null);
static Item **cache_converted_constant(THD *thd, Item **value,
Item **cache_item, Item_result type);
/**
Compare row signature of two expressions
@param item1 first expression
@param item2 second expression
@returns true if row types are compatible, false otherwise.
The function checks that two expressions have compatible row signatures
i.e. that the number of columns they return are the same and that if they
are both row expressions then each component from the first expression has
a row signature compatible with the signature of the corresponding component
of the second expression.
*/
static bool row_types_are_compatible(Item *item1, Item *item2) {
const uint n = item1->cols();
if (item2->check_cols(n)) return false;
for (uint i = 0; i < n; i++) {
if (item2->element_index(i)->check_cols(item1->element_index(i)->cols()) ||
(item1->element_index(i)->result_type() == ROW_RESULT &&
!row_types_are_compatible(item1->element_index(i),
item2->element_index(i))))
return false;
}
return true;
}
/**
Aggregates result types from the array of items.
This function aggregates result types from the array of items. Found type
supposed to be used later for comparison of values of these items.
Aggregation itself is performed by the item_cmp_type() function.
@param items array of items to aggregate the type from
@param nitems number of items in the array
@returns the aggregated type
*/
static Item_result agg_cmp_type(Item **items, uint nitems) {
Item_result type = items[0]->result_type();
for (uint i = 1; i < nitems; i++) {
type = item_cmp_type(type, items[i]->result_type());
}
return type;
}
static void write_histogram_to_trace(THD *thd, const Item_func *item,
const double selectivity) {
Opt_trace_object obj(&thd->opt_trace, "histogram_selectivity");
obj.add("condition", item).add("histogram_selectivity", selectivity);
}
/**
@brief Aggregates field types from the array of items.
@param[in] items array of items to aggregate the type from
@param[in] nitems number of items in the array
@details This function aggregates field types from the array of items.
Found type is supposed to be used later as the result field type
of a multi-argument function.
Aggregation itself is performed by the Field::field_type_merge()
function.
@note The term "aggregation" is used here in the sense of inferring the
result type of a function from its argument types.
@return aggregated field type.
*/
enum_field_types agg_field_type(Item **items, uint nitems) {
assert(nitems > 0 && items[0]->result_type() != ROW_RESULT);
enum_field_types res = items[0]->data_type();
for (uint i = 1; i < nitems; i++)
res = Field::field_type_merge(res, items[i]->data_type());
return real_type_to_type(res);
}
/**
Collects different types for comparison of first item with each other items
@param items Array of items to collect types from
@param nitems Number of items in the array
@param skip_nulls Don't collect types of NULL items if true
@note
This function collects different result types for comparison of the first
item in the list with each of the remaining items in the 'items' array.
@retval 0 Error, row type incompatibility has been detected
@retval <> 0 Bitmap of collected types - otherwise
*/
static uint collect_cmp_types(Item **items, uint nitems,
bool skip_nulls = false) {
const Item_result left_result = items[0]->result_type();
assert(nitems > 1);
uint found_types = 0;
for (uint i = 1; i < nitems; i++) {
if (skip_nulls && items[i]->type() == Item::NULL_ITEM)
continue; // Skip NULL constant items
if ((left_result == ROW_RESULT || items[i]->result_type() == ROW_RESULT) &&
!row_types_are_compatible(items[0], items[i]))
return 0;
found_types |=
1U << (uint)item_cmp_type(left_result, items[i]->result_type());
}
/*
Even if all right-hand items are NULLs and we are skipping them all, we need
at least one type bit in the found_type bitmask.
*/
if (skip_nulls && !found_types) found_types = 1U << (uint)left_result;
return found_types;
}
static void my_coll_agg_error(DTCollation &c1, DTCollation &c2,
const char *fname) {
my_error(ER_CANT_AGGREGATE_2COLLATIONS, MYF(0), c1.collation->m_coll_name,
c1.derivation_name(), c2.collation->m_coll_name,
c2.derivation_name(), fname);
}
/// This is used to indicate that the selectivity of a predicate has
/// not been determined.
static constexpr double kUndefinedSelectivity{-1.0};
/**
Try to find the selectivity of an Item_func (predicate) using a
histogram.
@param thd The current thread.
@param field The field for which we will look for a histogram.
@param op The comparison operator of item_func.
@param item_func The predicate.
@return The selectivity if a histogram was found and the arguments
of item_func allowed use of a histogram. Otherwise, kUndefinedSelectivity.
*/
static double get_histogram_selectivity(THD *thd, const Field &field,
histograms::enum_operator op,
const Item_func &item_func) {
const histograms::Histogram *histogram =
field.table->find_histogram(field.field_index());
if (histogram != nullptr) {
double selectivity;
if (!histogram->get_selectivity(item_func.arguments(),
item_func.argument_count(), op,
&selectivity)) {
if (unlikely(thd->opt_trace.is_started()))
write_histogram_to_trace(thd, &item_func, selectivity);
return selectivity;
}
}
return kUndefinedSelectivity;
}
/**
Estimate the selectivity of a predicate of type field=expression,
using an index containing 'field'. ('expression' is assumed to be
independent of the table that 'field' belongs to, meaning that this
function should not be called for e.g. "t1.f1=t1.f2+1").
@param field The field for which we estimate the selectivity.
@returns The selectivity estimate, or kUndefinedSelectivity if no
suitable index was found.
*/
static double IndexSelectivityOfUnknownValue(const Field &field) {
const ha_rows row_count{field.table->file->stats.records};
int contributing_keys{0};
double selectivity_product{-1.0};
if (row_count == 0) {
return kUndefinedSelectivity;
}
uint shortest_prefix{UINT_MAX};
// Loop over the keys containing 'field'.
for (uint key_no = field.part_of_key.get_first_set(); key_no != MY_BIT_NONE;
key_no = field.part_of_key.get_next_set(key_no)) {
const KEY &key{field.table->key_info[key_no]};
// Loop over the fields of 'key'.
for (uint part_no = 0; part_no < key.user_defined_key_parts; part_no++) {
if (!key.has_records_per_key(part_no)) {
break;
}
const Field &key_field{*key.key_part[part_no].field};
// Find (the square of) a selectivity estimate for a field that is part of
// an index, but not the first field of that index.
const auto subsequent_field_selectivity_squared = [&]() {
assert(part_no > 0);
/*
For a field that is the first part (zero-indexed) of a key we
can obtain the number of distinct values directly from the
records_per_key statistic, but if the field is the k'th > 0
part we have to make an estimate. Let d_k denote the number of
distinct values in the k-part prefix of the key. Given that we
only have information about d_k and d_(k-1) the number of
distinct values in the field can be anywhere between d_k and
d_k / d_(k-1), so we use the geometric mean of these two
values as our estimate.
*/
// Case 1: key field 'part_no' and the preceding fields are
// uncorrelated.
const double uncorrelated_estimate{
double{key.records_per_key(part_no)} /
key.records_per_key(part_no - 1)};
// Case 2: The preceding fields are functionally dependent on
// key field 'part_no'.
const double correlated_estimate{
std::min(1.0, double{key.records_per_key(part_no)} / row_count)};
// Use the geometric mean of case 1 and 2.
return uncorrelated_estimate * correlated_estimate;
};
if (&field == &key_field) {
if (part_no == 0) {
// We need std::min() since records_per_key() and stats.records
// may be updated at different points in time.
return std::min(1.0, double{key.records_per_key(0)} / row_count);
} else if (part_no < shortest_prefix) {
shortest_prefix = part_no;
selectivity_product = subsequent_field_selectivity_squared();
contributing_keys = 1;
break;
} else if (part_no == shortest_prefix) {
// If 'field' is the n'th part of several indexes, we calculate the
// geometric mean of the estimate from each of them.
selectivity_product *= subsequent_field_selectivity_squared();
contributing_keys++;
break;
}
}
}
}
switch (contributing_keys) {
case 0:
return kUndefinedSelectivity;
case 1:
return std::sqrt(
selectivity_product); // Minor optimization for the most common case.
default:
return std::pow(selectivity_product, 0.5 / contributing_keys);
}
}
/**
This implementation of the factory method also implements flattening of
row constructors. Examples of flattening are:
- ROW(a, b) op ROW(x, y) => a op x P b op y.
- ROW(a, ROW(b, c) op ROW(x, ROW(y, z))) => a op x P b op y P c op z.
P is either AND or OR, depending on the comparison operation, and this
detail is left for combine().
The actual operator @c op is created by the concrete subclass in
create_scalar_predicate().
*/
Item_bool_func *Linear_comp_creator::create(Item *a, Item *b) const {
/*
Test if the arguments are row constructors and thus can be flattened into
a list of ANDs or ORs.
*/
if (a->type() == Item::ROW_ITEM && b->type() == Item::ROW_ITEM) {
if (a->cols() != b->cols()) {
my_error(ER_OPERAND_COLUMNS, MYF(0), a->cols());
return nullptr;
}
assert(a->cols() > 1);
List<Item> list;
for (uint i = 0; i < a->cols(); ++i)
list.push_back(create(a->element_index(i), b->element_index(i)));
return combine(list);
}
return create_scalar_predicate(a, b);
}
Item_bool_func *Eq_creator::create_scalar_predicate(Item *a, Item *b) const {
assert(a->type() != Item::ROW_ITEM || b->type() != Item::ROW_ITEM);
return new Item_func_eq(a, b);
}
Item_bool_func *Eq_creator::combine(List<Item> list) const {
return new Item_cond_and(list);
}
Item_bool_func *Equal_creator::create_scalar_predicate(Item *a, Item *b) const {
assert(a->type() != Item::ROW_ITEM || b->type() != Item::ROW_ITEM);
return new Item_func_equal(a, b);
}
Item_bool_func *Equal_creator::combine(List<Item> list) const {
return new Item_cond_and(list);
}
Item_bool_func *Ne_creator::create_scalar_predicate(Item *a, Item *b) const {
assert(a->type() != Item::ROW_ITEM || b->type() != Item::ROW_ITEM);
return new Item_func_ne(a, b);
}
Item_bool_func *Ne_creator::combine(List<Item> list) const {
return new Item_cond_or(list);
}
Item_bool_func *Gt_creator::create(Item *a, Item *b) const {
return new Item_func_gt(a, b);
}
Item_bool_func *Lt_creator::create(Item *a, Item *b) const {
return new Item_func_lt(a, b);
}
Item_bool_func *Ge_creator::create(Item *a, Item *b) const {
return new Item_func_ge(a, b);
}
Item_bool_func *Le_creator::create(Item *a, Item *b) const {
return new Item_func_le(a, b);
}
float Item_func_not::get_filtering_effect(THD *thd, table_map filter_for_table,
table_map read_tables,
const MY_BITMAP *fields_to_ignore,
double rows_in_table) {
const float filter = args[0]->get_filtering_effect(
thd, filter_for_table, read_tables, fields_to_ignore, rows_in_table);
/*
If the predicate that will be negated has COND_FILTER_ALLPASS
filtering it means that some dependent tables have not been
read, that the predicate is of a type that filtering effect is
not calculated for or something similar. In any case, the
filtering effect of the inverted predicate should also be
COND_FILTER_ALLPASS.
*/
if (filter == COND_FILTER_ALLPASS) return COND_FILTER_ALLPASS;
return 1.0f - filter;
}
/*
Test functions
Most of these returns 0LL if false and 1LL if true and
NULL if some arg is NULL.
*/
longlong Item_func_not::val_int() {
assert(fixed);
const bool value = args[0]->val_bool();
null_value = args[0]->null_value;
/*
If NULL, return 0 because some higher layers like
evaluate_join_record() just test for !=0 to implement IS TRUE.
If not NULL, return inverted value.
*/
return ((!null_value && value == 0) ? 1 : 0);
}
/*
We put any NOT expression into parenthesis to avoid
possible problems with internal view representations where
any '!' is converted to NOT. It may cause a problem if
'!' is used in an expression together with other operators
whose precedence is lower than the precedence of '!' yet
higher than the precedence of NOT.
*/
void Item_func_not::print(const THD *thd, String *str,
enum_query_type query_type) const {
str->append('(');
Item_func::print(thd, str, query_type);
str->append(')');
}
/**
special NOT for ALL subquery.
*/
longlong Item_func_not_all::val_int() {
assert(fixed);
const bool value = args[0]->val_bool();
/*
return TRUE if there was no record in underlying select in max/min
optimization (ALL subquery)
*/
if (empty_underlying_subquery()) return 1;
null_value = args[0]->null_value;
return ((!null_value && value == 0) ? 1 : 0);
}
bool Item_func_not_all::empty_underlying_subquery() {
assert(subselect != nullptr ||
!(test_sum_item != nullptr || test_sub_item != nullptr));
/*
When outer argument is NULL the subquery has not yet been evaluated, we
need to evaluate it to get to know whether it returns any rows to return
the correct result. 'ANY' subqueries are an exception because the
result would be false or null which for a top level item always mean false.
The subselect->unit->item->... chain should be used instead of
subselect->... to workaround subquery transformation which could make
subselect->engine unusable.
*/
if (subselect != nullptr &&
subselect->subquery_type() != Item_subselect::ANY_SUBQUERY &&
subselect->query_expr()->item != nullptr &&
!subselect->query_expr()->item->is_evaluated())
subselect->query_expr()->item->exec(current_thd);
return (test_sum_item != nullptr && !test_sum_item->has_values()) ||
(test_sub_item != nullptr && !test_sub_item->has_values());
}
void Item_func_not_all::print(const THD *thd, String *str,
enum_query_type query_type) const {
if (show)
Item_func::print(thd, str, query_type);
else
args[0]->print(thd, str, query_type);
}
/**
Special NOP (No OPeration) for ALL subquery. It is like
Item_func_not_all.
@return
(return TRUE if underlying subquery do not return rows) but if subquery
returns some rows it return same value as argument (TRUE/FALSE).
*/
longlong Item_func_nop_all::val_int() {
assert(fixed);
const longlong value = args[0]->val_int();
/*
return FALSE if there was records in underlying select in max/min
optimization (SAME/ANY subquery)
*/
if (empty_underlying_subquery()) return 0;
null_value = args[0]->null_value;
return (null_value || value == 0) ? 0 : 1;
}
/**
Return an an unsigned Item_int containing the value of the year as stored in
field. The item is typed as a YEAR.
@param field the field containign the year value
@return the year wrapped in an Item in as described above, or nullptr on
error.
*/
static Item *make_year_constant(Field *field) {
Item_int *year = new Item_int(field->val_int());
if (year == nullptr) return nullptr;
year->unsigned_flag = field->is_flag_set(UNSIGNED_FLAG);
year->set_data_type(MYSQL_TYPE_YEAR);
return year;
}
/**
Convert a constant item to an int and replace the original item.
The function converts a constant expression or string to an integer.
On successful conversion the original item is substituted for the
result of the item evaluation.
This is done when comparing DATE/TIME of different formats and
also when comparing bigint to strings (in which case strings
are converted to bigints).
@param thd thread handle
@param field_item item will be converted using the type of this field
@param[in,out] item reference to the item to convert
@param[out] converted True if a replacement was done.
@note
This function may be called both at prepare and optimize stages.
When called at optimize stage, ensure that we record transient changes.
@returns false if success, true if error
*/
static bool convert_constant_item(THD *thd, Item_field *field_item, Item **item,
bool *converted) {
Field *field = field_item->field;
*converted = false;
if ((*item)->may_evaluate_const(thd) &&
/*
In case of GC it's possible that this func will be called on an
already converted constant. Don't convert it again.
*/
!((*item)->data_type() == field_item->data_type() &&
(*item)->basic_const_item())) {
TABLE *table = field->table;
const sql_mode_t orig_sql_mode = thd->variables.sql_mode;
const enum_check_fields orig_check_for_truncated_fields =
thd->check_for_truncated_fields;
my_bitmap_map *old_maps[2];
ulonglong orig_field_val = 0; /* original field value if valid */
old_maps[0] = nullptr;
old_maps[1] = nullptr;
if (table)
dbug_tmp_use_all_columns(table, old_maps, table->read_set,
table->write_set);
/* For comparison purposes allow invalid dates like 2000-01-32 */
thd->variables.sql_mode =
(orig_sql_mode & ~MODE_NO_ZERO_DATE) | MODE_INVALID_DATES;
thd->check_for_truncated_fields = CHECK_FIELD_IGNORE;
/*
Store the value of the field/constant if it references an outer field
because the call to save_in_field below overrides that value.
Don't save field value if no data has been read yet.
Outer constant values are always saved.
*/
bool save_field_value =
field_item->depended_from &&
(field_item->const_item() || field->table->has_row());
if (save_field_value) orig_field_val = field->val_int();
int rc;
if (!(*item)->is_null() &&
(((rc = (*item)->save_in_field(field, true)) == TYPE_OK) ||
rc == TYPE_NOTE_TIME_TRUNCATED)) // TS-TODO
{
int field_cmp = 0;
/*
If item is a decimal value, we must reject it if it was truncated.
TODO: consider doing the same for MYSQL_TYPE_YEAR,.
However: we have tests which assume that things '1999' and
'1991-01-01 01:01:01' can be converted to year.
Testing for MYSQL_TYPE_YEAR here, would treat such literals
as 'incorrect DOUBLE value'.
See Bug#13580652 YEAR COLUMN CAN BE EQUAL TO 1999.1
*/
if (field->type() == MYSQL_TYPE_LONGLONG) {
field_cmp = stored_field_cmp_to_item(thd, field, *item);
DBUG_PRINT("info", ("convert_constant_item %d", field_cmp));
}
// @todo it is not correct, in time_col = datetime_const_function,
// to convert the latter to Item_time_with_ref below. Time_col should
// rather be cast to datetime. WL#6570 check if the "fix temporals"
// patch fixes this.
if (0 == field_cmp) {
Item *tmp =
field->type() == MYSQL_TYPE_TIME
?
#define OLD_CMP
#ifdef OLD_CMP
new Item_time_with_ref(field->decimals(),
field->val_time_temporal(), *item)
:
#else
new Item_time_with_ref(
max((*item)->time_precision(), field->decimals()),
(*item)->val_time_temporal(), *item)
:
#endif
is_temporal_type_with_date(field->type())
?
#ifdef OLD_CMP
new Item_datetime_with_ref(field->type(), field->decimals(),
field->val_date_temporal(),
*item)
:
#else
new Item_datetime_with_ref(
field->type(),
max((*item)->datetime_precision(), field->decimals()),
(*item)->val_date_temporal(), *item)
:
#endif
field->type() == MYSQL_TYPE_YEAR
? make_year_constant(field)
: new Item_int_with_ref(
field->type(), field->val_int(), *item,
field->is_flag_set(UNSIGNED_FLAG));
if (tmp == nullptr) return true;
if (thd->lex->is_exec_started())
thd->change_item_tree(item, tmp);
else
*item = tmp;
*converted = true; // Item was replaced
}
}
/* Restore the original field value. */
if (save_field_value) {
*converted = field->store(orig_field_val, true);
/* orig_field_val must be a valid value that can be restored back. */
assert(!*converted);
}
thd->variables.sql_mode = orig_sql_mode;
thd->check_for_truncated_fields = orig_check_for_truncated_fields;
if (table)
dbug_tmp_restore_column_maps(table->read_set, table->write_set, old_maps);
}
return false;
}
bool Item_bool_func2::convert_constant_arg(THD *thd, Item *field, Item **item,
bool *converted) {
*converted = false;
if (field->real_item()->type() != FIELD_ITEM) return false;
Item_field *field_item = (Item_field *)(field->real_item());
if (field_item->field->can_be_compared_as_longlong() &&
!(field_item->is_temporal_with_date() &&
(*item)->result_type() == STRING_RESULT)) {
if (convert_constant_item(thd, field_item, item, converted)) return true;
if (*converted) {
if (cmp.set_cmp_func(this, args, args + 1, INT_RESULT)) return true;
field->cmp_context = (*item)->cmp_context = INT_RESULT;
}
}
return false;
}
bool Item_bool_func2::resolve_type(THD *thd) {
DBUG_TRACE;
// Both arguments are needed for type resolving
assert(args[0] && args[1]);
if (Item_bool_func::resolve_type(thd)) {
return true;
}
/*
See agg_item_charsets() in item.cc for comments
on character set and collation aggregation.
Charset comparison is skipped for SHOW CREATE VIEW
statements since the join fields are not resolved
during SHOW CREATE VIEW.
*/
if (thd->lex->sql_command != SQLCOM_SHOW_CREATE &&
args[0]->result_type() == STRING_RESULT &&
args[1]->result_type() == STRING_RESULT &&
agg_arg_charsets_for_comparison(cmp.cmp_collation, args, 2))
return true;
args[0]->cmp_context = args[1]->cmp_context =
item_cmp_type(args[0]->result_type(), args[1]->result_type());
/*
Geometry item cannot participate in an arithmetic or string comparison or
a full text search, except in equal/not equal comparison.
We allow geometry arguments in equal/not equal, since such
comparisons are used now and are meaningful, although it simply compares
the GEOMETRY byte string rather than doing a geometric equality comparison.
*/
const Functype func_type = functype();
if ((func_type == LT_FUNC || func_type == LE_FUNC || func_type == GE_FUNC ||
func_type == GT_FUNC || func_type == FT_FUNC) &&
reject_geometry_args(arg_count, args, this))
return true;
// Make a special case of compare with fields to get nicer DATE comparisons
if (!(thd->lex->is_view_context_analysis())) {
bool cvt1, cvt2;
if (convert_constant_arg(thd, args[0], &args[1], &cvt1) ||
convert_constant_arg(thd, args[1], &args[0], &cvt2))
return true;
if (cvt1 || cvt2) return false;
}
if (marker == MARKER_IMPLICIT_NE_ZERO) { // Results may surprise
if (args[1]->result_type() == STRING_RESULT &&
args[1]->data_type() == MYSQL_TYPE_JSON)
push_warning(thd, Sql_condition::SL_WARNING,
ER_IMPLICIT_COMPARISON_FOR_JSON,
ER_THD(thd, ER_IMPLICIT_COMPARISON_FOR_JSON));
}
return (thd->lex->sql_command != SQLCOM_SHOW_CREATE) ? set_cmp_func() : false;
}
bool Item_func_like::resolve_type(THD *thd) {
// Function returns 0 or 1
max_length = 1;
// Determine the common character set for all arguments
if (agg_arg_charsets_for_comparison(cmp.cmp_collation, args, arg_count))
return true;
for (uint i = 0; i < arg_count; i++) {
if (args[i]->data_type() == MYSQL_TYPE_INVALID &&
args[i]->propagate_type(
thd,
Type_properties(MYSQL_TYPE_VARCHAR, cmp.cmp_collation.collation))) {
return true;
}
}
if (reject_geometry_args(arg_count, args, this)) return true;
// LIKE is always carried out as a string operation
args[0]->cmp_context = STRING_RESULT;
args[1]->cmp_context = STRING_RESULT;
if (arg_count > 2) {
args[2]->cmp_context = STRING_RESULT;
// ESCAPE clauses that vary per row are not valid:
if (!args[2]->const_for_execution()) {
my_error(ER_WRONG_ARGUMENTS, MYF(0), "ESCAPE");
return true;
}
}
/*
If the escape item is const, evaluate it now, so that the range optimizer
can try to optimize LIKE 'foo%' into a range query.
TODO: If we move this into escape_is_evaluated(), which is called later,
we might be able to optimize more cases.
*/
if (!escape_was_used_in_parsing() || args[2]->const_item()) {
escape_is_const = true;
if (!(thd->lex->context_analysis_only & CONTEXT_ANALYSIS_ONLY_VIEW)) {
if (eval_escape_clause(thd)) return true;
if (check_covering_prefix_keys(thd)) return true;
}
}
return false;
}
Item *Item_func_like::replace_scalar_subquery(uchar *) {
// Replacing a scalar subquery with a reference to a column in a derived table
// could change the constness. Check that the ESCAPE clause is still
// const_for_execution().
if (escape_was_used_in_parsing() && !args[2]->const_for_execution()) {
my_error(ER_WRONG_ARGUMENTS, MYF(0), "ESCAPE");
return nullptr;
}
return this;
}
Item *Item_bool_func2::replace_scalar_subquery(uchar *) {
if (set_cmp_func()) {
return nullptr;
}
return this;
}
void Arg_comparator::cleanup() {
if (comparators != nullptr) {
/*
We cannot rely on (*left)->cols(), since *left may be deallocated
at this point, so use comparator_count to loop.
*/
for (size_t i = 0; i < comparator_count; i++) {
comparators[i].cleanup();
}
}
if (json_scalar != nullptr) {
::destroy_at(json_scalar);
json_scalar = nullptr;
}
value1.mem_free();
value2.mem_free();
}
bool Arg_comparator::set_compare_func(Item_result_field *item,
Item_result type) {
m_compare_type = type;
owner = item;
func = comparator_matrix[type];
switch (type) {
case ROW_RESULT: {
const uint n = (*left)->cols();
if (n != (*right)->cols()) {
my_error(ER_OPERAND_COLUMNS, MYF(0), n);
comparators = nullptr;
return true;
}
if (!(comparators = new (*THR_MALLOC) Arg_comparator[n])) return true;
comparator_count = n;
for (uint i = 0; i < n; i++) {
if ((*left)->element_index(i)->cols() !=
(*right)->element_index(i)->cols()) {
my_error(ER_OPERAND_COLUMNS, MYF(0),
(*left)->element_index(i)->cols());
return true;
}
if (comparators[i].set_cmp_func(owner, (*left)->addr(i),
(*right)->addr(i), set_null))
return true;
}
break;
}
case STRING_RESULT: {
/*
We must set cmp_charset here as we may be called from for an automatic
generated item, like in natural join
*/
if (cmp_collation.set((*left)->collation, (*right)->collation,
MY_COLL_CMP_CONV) ||
cmp_collation.derivation == DERIVATION_NONE) {
const char *func_name = owner ? owner->func_name() : "";
my_coll_agg_error((*left)->collation, (*right)->collation, func_name);
return true;
}
if (cmp_collation.collation == &my_charset_bin) {
/*
We are using BLOB/BINARY/VARBINARY, change to compare byte by byte,
without removing end space
*/
if (func == &Arg_comparator::compare_string)
func = &Arg_comparator::compare_binary_string;
}
/*
If the comparison's and arguments' collations differ, prevent column
substitution. Otherwise we would get into trouble with comparisons
like:
WHERE col = 'j' AND col = BINARY 'j'
which would be transformed to:
WHERE col = 'j' AND 'j' = BINARY 'j', then to:
WHERE col = 'j'. That would be wrong, if col contains 'J'.
*/
if ((*left)->collation.collation != cmp_collation.collation)
(*left)->walk(&Item::disable_constant_propagation, enum_walk::POSTFIX,
nullptr);
if ((*right)->collation.collation != cmp_collation.collation)
(*right)->walk(&Item::disable_constant_propagation, enum_walk::POSTFIX,
nullptr);
break;
}
case INT_RESULT: {
if ((*left)->is_temporal() && (*right)->is_temporal()) {
func = &Arg_comparator::compare_time_packed;
} else if (func == &Arg_comparator::compare_int_signed) {
if ((*left)->unsigned_flag)
func = (((*right)->unsigned_flag)
? &Arg_comparator::compare_int_unsigned
: &Arg_comparator::compare_int_unsigned_signed);
else if ((*right)->unsigned_flag)
func = &Arg_comparator::compare_int_signed_unsigned;
}
break;
}
case DECIMAL_RESULT:
break;
case REAL_RESULT: {
if ((*left)->decimals < DECIMAL_NOT_SPECIFIED &&
(*right)->decimals < DECIMAL_NOT_SPECIFIED) {
precision = 5 / log_10[max((*left)->decimals, (*right)->decimals) + 1];
if (func == &Arg_comparator::compare_real)
func = &Arg_comparator::compare_real_fixed;
}
break;
}
default:
assert(0);
}
return false;
}
/**
A minion of get_mysql_time_from_str, see its description.
This version doesn't issue any warnings, leaving that to its parent.
This method has one extra argument which return warnings.
@param[in] thd Thread handle
@param[in] str A string to convert
@param[out] l_time The MYSQL_TIME objects is initialized.
@param[in, out] status Any warnings given are returned here
@returns true if error
*/
bool get_mysql_time_from_str_no_warn(THD *thd, String *str, MYSQL_TIME *l_time,
MYSQL_TIME_STATUS *status) {
my_time_flags_t flags = TIME_FUZZY_DATE | TIME_INVALID_DATES;
if (thd->variables.sql_mode & MODE_NO_ZERO_IN_DATE)
flags |= TIME_NO_ZERO_IN_DATE;
if (thd->variables.sql_mode & MODE_NO_ZERO_DATE) flags |= TIME_NO_ZERO_DATE;
if (thd->is_fsp_truncate_mode()) flags |= TIME_FRAC_TRUNCATE;
return str_to_datetime(str, l_time, flags, status);
}
/**
Parse date provided in a string to a MYSQL_TIME.
@param[in] thd Thread handle
@param[in] str A string to convert
@param[in] warn_type Type of the timestamp for issuing the warning
@param[in] warn_name Field name for issuing the warning
@param[out] l_time The MYSQL_TIME objects is initialized.
Parses a date provided in the string str into a MYSQL_TIME object. If the
string contains an incorrect date or doesn't correspond to a date at all
then a warning is issued. The warn_type and the warn_name arguments are used
as the name and the type of the field when issuing the warning. If any input
was discarded (trailing or non-timestamp-y characters), return value will be
true.
@return Status flag
@retval false Success.
@retval True Indicates failure.
*/
bool get_mysql_time_from_str(THD *thd, String *str,
enum_mysql_timestamp_type warn_type,
const char *warn_name, MYSQL_TIME *l_time) {
bool value;
MYSQL_TIME_STATUS status;
my_time_flags_t flags = TIME_FUZZY_DATE;
if (thd->variables.sql_mode & MODE_NO_ZERO_IN_DATE)
flags |= TIME_NO_ZERO_IN_DATE;
if (thd->variables.sql_mode & MODE_NO_ZERO_DATE) flags |= TIME_NO_ZERO_DATE;
if (thd->is_fsp_truncate_mode()) flags |= TIME_FRAC_TRUNCATE;
if (thd->variables.sql_mode & MODE_INVALID_DATES) flags |= TIME_INVALID_DATES;
if (!propagate_datetime_overflow(
thd, &status.warnings,
str_to_datetime(str, l_time, flags, &status)) &&
(l_time->time_type == MYSQL_TIMESTAMP_DATETIME ||
l_time->time_type == MYSQL_TIMESTAMP_DATETIME_TZ ||
l_time->time_type == MYSQL_TIMESTAMP_DATE)) {
/*
Do not return yet, we may still want to throw a "trailing garbage"
warning.
*/
check_deprecated_datetime_format(thd, str->charset(), status);
value = false;
} else {
value = true;
status.warnings = MYSQL_TIME_WARN_TRUNCATED; /* force warning */
}
if (status.warnings > 0) {
if (make_truncated_value_warning(thd, Sql_condition::SL_WARNING,
ErrConvString(str), warn_type, warn_name))
return true;
}
return value;
}
/**
@brief Convert date provided in a string
to its packed temporal int representation.
@param[in] thd thread handle
@param[in] str a string to convert
@param[in] warn_type type of the timestamp for issuing the warning
@param[in] warn_name field name for issuing the warning
@param[out] error_arg could not extract a DATE or DATETIME
@details Convert date provided in the string str to the int
representation. If the string contains wrong date or doesn't
contain it at all then a warning is issued. The warn_type and
the warn_name arguments are used as the name and the type of the
field when issuing the warning.
@return
converted value. 0 on error and on zero-dates -- check 'failure'
*/
static ulonglong get_date_from_str(THD *thd, String *str,
enum_mysql_timestamp_type warn_type,
const char *warn_name, bool *error_arg) {
MYSQL_TIME l_time;
*error_arg = get_mysql_time_from_str(thd, str, warn_type, warn_name, &l_time);
if (*error_arg) return 0;
return TIME_to_longlong_datetime_packed(l_time);
}
/**
Check if str_arg is a constant and convert it to datetime packed value.
Note, const_value may stay untouched, so the caller is responsible to
initialize it.
@param date_arg date argument, its name is used for error
reporting.
@param str_arg string argument to get datetime value from.
@param[in,out] const_value If not nullptr, the converted value is stored
here. To detect that conversion was not possible,
the caller is responsible for initializing this
value to MYSQL_TIMESTAMP_ERROR before calling
and checking the value has changed after the call.
@return true on error, false on success, false if str_arg is not a const.
*/
bool Arg_comparator::get_date_from_const(Item *date_arg, Item *str_arg,
ulonglong *const_value) {
THD *thd = current_thd;
assert(str_arg->result_type() == STRING_RESULT);
/*
Don't use cache while in the context analysis mode only (i.e. for
EXPLAIN/CREATE VIEW and similar queries). Cache is useless in such
cases and can cause problems. For example evaluating subqueries can
confuse storage engines since in context analysis mode tables
aren't locked.
*/
if (!(thd->lex->context_analysis_only & CONTEXT_ANALYSIS_ONLY_VIEW) &&
str_arg->may_evaluate_const(thd)) {
ulonglong value;
if (str_arg->data_type() == MYSQL_TYPE_TIME) {
// Convert from TIME to DATETIME numeric packed value
value = str_arg->val_date_temporal();
if (str_arg->null_value) return true;
} else {
// Convert from string to DATETIME numeric packed value
const enum_field_types date_arg_type = date_arg->data_type();
const enum_mysql_timestamp_type t_type =
(date_arg_type == MYSQL_TYPE_DATE ? MYSQL_TIMESTAMP_DATE
: MYSQL_TIMESTAMP_DATETIME);
String tmp;
String *str_val = str_arg->val_str(&tmp);
if (str_arg->null_value) return true;
bool error;
value = get_date_from_str(thd, str_val, t_type, date_arg->item_name.ptr(),
&error);
if (error) {
const char *typestr = (date_arg_type == MYSQL_TYPE_DATE) ? "DATE"
: (date_arg_type == MYSQL_TYPE_DATETIME)
? "DATETIME"
: "TIMESTAMP";
const ErrConvString err(str_val->ptr(), str_val->length(),
thd->variables.character_set_client);
my_error(ER_WRONG_VALUE, MYF(0), typestr, err.ptr());
return true;
}
}
if (const_value) *const_value = value;
}
return false;
}
/**
Checks whether compare_datetime() can be used to compare items.
SYNOPSIS
Arg_comparator::can_compare_as_dates()
left, right [in] items to be compared
DESCRIPTION
Checks several cases when the DATETIME comparator should be used.
The following cases are accepted:
1. Both left and right is a DATE/DATETIME/TIMESTAMP field/function
returning string or int result.
2. Only left or right is a DATE/DATETIME/TIMESTAMP field/function
returning string or int result and the other item (right or left) is an
item with string result.
This doesn't mean that the string can necessarily be successfully converted to
a datetime value. But if it cannot this will lead to an error later,
@see Arg_comparator::get_date_from_const
In all other cases (date-[int|real|decimal]/[int|real|decimal]-date)
the comparison is handled by other comparators.
@return true if the Arg_comparator::compare_datetime should be used,
false otherwise
*/
bool Arg_comparator::can_compare_as_dates(const Item *left, const Item *right) {
if (left->type() == Item::ROW_ITEM || right->type() == Item::ROW_ITEM)
return false;
if (left->is_temporal_with_date() &&
(right->result_type() == STRING_RESULT || right->is_temporal_with_date()))
return true;
else
return left->result_type() == STRING_RESULT &&
right->is_temporal_with_date();
}
/**
Retrieves correct TIME value from the given item.
@param [in,out] item_arg item to retrieve TIME value from
@param [out] is_null true <=> the item_arg is null
@returns obtained value
Retrieves the correct TIME value from given item for comparison by the
compare_datetime() function.
If item's result can be compared as longlong then its int value is used
and a value returned by get_time function is used otherwise.
*/
static longlong get_time_value(THD *, Item ***item_arg, Item **, const Item *,
bool *is_null) {
longlong value = 0;
Item *item = **item_arg;
String buf, *str = nullptr;
if (item->data_type() == MYSQL_TYPE_TIME ||
item->data_type() == MYSQL_TYPE_NULL) {
value = item->val_time_temporal();
*is_null = item->null_value;
} else {
str = item->val_str(&buf);
*is_null = item->null_value;
}
if (*is_null) return ~(ulonglong)0;
/*
Convert strings to the integer TIME representation.
*/
if (str) {
MYSQL_TIME l_time;
if (str_to_time_with_warn(str, &l_time)) {
*is_null = true;
return ~(ulonglong)0;
}
value = TIME_to_longlong_datetime_packed(l_time);
}
return value;
}
/**
Sets compare functions for various datatypes.
It additionally sets up Item_cache objects for caching any constant values
that need conversion to a type compatible with the comparator type, to avoid
the need for performing the conversion again each time the comparator is
invoked.
NOTE
The result type of a comparison is chosen by item_cmp_type().
Here we override the chosen result type for certain expression
containing date or time or decimal expressions.
*/
bool Arg_comparator::set_cmp_func(Item_result_field *owner_arg, Item **left_arg,
Item **right_arg, Item_result type) {
m_compare_type = type;
owner = owner_arg;
set_null = set_null && owner_arg;
left = left_arg;
right = right_arg;
if (type != ROW_RESULT && (((*left)->result_type() == STRING_RESULT &&
(*left)->data_type() == MYSQL_TYPE_JSON) ||
((*right)->result_type() == STRING_RESULT &&
(*right)->data_type() == MYSQL_TYPE_JSON))) {
// Use the JSON comparator if at least one of the arguments is JSON.
func = &Arg_comparator::compare_json;
m_compare_type = STRING_RESULT;
// Convention: Immediate dynamic parameters are handled as scalars:
(*left)->mark_json_as_scalar();
(*right)->mark_json_as_scalar();
return false;
}
/*
Checks whether at least one of the arguments is DATE/DATETIME/TIMESTAMP
and the other one is also DATE/DATETIME/TIMESTAMP or a constant string.
*/
if (can_compare_as_dates(*left, *right)) {
left_cache = nullptr;
right_cache = nullptr;
ulonglong numeric_datetime = static_cast<ulonglong>(MYSQL_TIMESTAMP_ERROR);
/*
If one of the arguments is constant string, try to convert it
to DATETIME and cache it.
*/
if (!(*left)->is_temporal_with_date()) {
if (!get_date_from_const(*right, *left, &numeric_datetime) &&
numeric_datetime != static_cast<ulonglong>(MYSQL_TIMESTAMP_ERROR)) {
auto *cache = new Item_cache_datetime(MYSQL_TYPE_DATETIME);
// OOM
if (!cache) return true; /* purecov: inspected */
cache->store_value((*left), numeric_datetime);
// Mark the cache as non-const to prevent re-caching.
cache->set_used_tables(1);
left_cache = cache;
left = &left_cache;
}
} else if (!(*right)->is_temporal_with_date()) {
if (!get_date_from_const(*left, *right, &numeric_datetime) &&
numeric_datetime != static_cast<ulonglong>(MYSQL_TIMESTAMP_ERROR)) {
auto *cache = new Item_cache_datetime(MYSQL_TYPE_DATETIME);
// OOM
if (!cache) return true; /* purecov: inspected */
cache->store_value((*right), numeric_datetime);
// Mark the cache as non-const to prevent re-caching.
cache->set_used_tables(1);
right_cache = cache;
right = &right_cache;
}
}
if (current_thd->is_error()) return true;
func = &Arg_comparator::compare_datetime;
get_value_a_func = &get_datetime_value;
get_value_b_func = &get_datetime_value;
cmp_collation.set(&my_charset_numeric);
set_cmp_context_for_datetime();
return false;
} else if ((type == STRING_RESULT ||
// When comparing time field and cached/converted time constant
type == REAL_RESULT) &&
(*left)->data_type() == MYSQL_TYPE_TIME &&
(*right)->data_type() == MYSQL_TYPE_TIME) {
/* Compare TIME values as integers. */
left_cache = nullptr;
right_cache = nullptr;
func = &Arg_comparator::compare_datetime;
get_value_a_func = &get_time_value;
get_value_b_func = &get_time_value;
set_cmp_context_for_datetime();
return false;
} else if (type == STRING_RESULT && (*left)->result_type() == STRING_RESULT &&
(*right)->result_type() == STRING_RESULT) {
DTCollation coll;
coll.set((*left)->collation, (*right)->collation, MY_COLL_CMP_CONV);
/*
DTCollation::set() may have chosen a charset that's a superset of both
and "left" and "right", so we need to convert both items.
*/
const char *func_name = owner ? owner->func_name() : "";
if (agg_item_set_converter(coll, func_name, left, 1, MY_COLL_CMP_CONV, 1,
true) ||
agg_item_set_converter(coll, func_name, right, 1, MY_COLL_CMP_CONV, 1,
true))
return true;
} else if (try_year_cmp_func(type)) {
return false;
} else if (type == REAL_RESULT &&
(((*left)->result_type() == DECIMAL_RESULT &&
!(*left)->const_item() &&
(*right)->result_type() == STRING_RESULT &&
(*right)->const_item()) ||
((*right)->result_type() == DECIMAL_RESULT &&
!(*right)->const_item() &&
(*left)->result_type() == STRING_RESULT &&
(*left)->const_item()))) {
/*
<non-const decimal expression> <cmp> <const string expression>
or
<const string expression> <cmp> <non-const decimal expression>
Do comparison as decimal rather than float, in order not to lose precision.
*/
type = DECIMAL_RESULT;
}
THD *thd = current_thd;
left = cache_converted_constant(thd, left, &left_cache, type);
right = cache_converted_constant(thd, right, &right_cache, type);
return set_compare_func(owner_arg, type);
}
bool Arg_comparator::set_cmp_func(Item_result_field *owner_arg, Item **left_arg,
Item **right_arg, bool set_null_arg) {
set_null = set_null_arg;
const Item_result item_result =
item_cmp_type((*left_arg)->result_type(), (*right_arg)->result_type());
return set_cmp_func(owner_arg, left_arg, right_arg, item_result);
}
bool Arg_comparator::set_cmp_func(Item_result_field *owner_arg, Item **left_arg,
Item **right_arg, bool set_null_arg,
Item_result type) {
set_null = set_null_arg;
return set_cmp_func(owner_arg, left_arg, right_arg, type);
}
/**
Wraps the item into a CAST function to the type provided as argument
@param item - the item to be wrapped
@param type - the type to wrap the item to
@returns true if error (OOM), false otherwise.
*/
inline bool wrap_in_cast(Item **item, enum_field_types type) {
THD *thd = current_thd;
Item *cast = nullptr;
switch (type) {
case MYSQL_TYPE_DATETIME: {
cast = new Item_typecast_datetime(*item, false);
break;
}
case MYSQL_TYPE_DATE: {
cast = new Item_typecast_date(*item, false);
break;
}
case MYSQL_TYPE_TIME: {
cast = new Item_typecast_time(*item);
break;
}
case MYSQL_TYPE_DOUBLE: {
cast = new Item_typecast_real(*item);
break;
}
default: {
assert(false);
return true;
}
}
if (cast == nullptr) return true;
if (cast->fix_fields(thd, item)) return true;
thd->change_item_tree(item, cast);
return false;
}
/**
* Checks that the argument is an aggregation function, window function, a
* built-in non-constant function or a non-constant field.
* WL#12108: it excludes stored procedures and functions, user defined
* functions and also does not update the content of expressions
* inside Value_generator since Optimize is not called after the expression
* is unpacked.
* @param item to be checked
* @return true for non-const field or functions, false otherwise
*/
inline bool is_non_const_field_or_function(const Item &item) {
return !item.const_for_execution() &&
(item.type() == Item::FIELD_ITEM || item.type() == Item::FUNC_ITEM ||
item.type() == Item::SUM_FUNC_ITEM);
}
bool Arg_comparator::inject_cast_nodes() {
// If the comparator is set to one that compares as floating point numbers.
if (func == &Arg_comparator::compare_real ||
func == &Arg_comparator::compare_real_fixed) {
Item *aa = (*left)->real_item();
Item *bb = (*right)->real_item();
// No cast nodes are injected if both arguments are numeric
// (that includes YEAR data type)
if (!((aa->result_type() == STRING_RESULT &&
(bb->result_type() == INT_RESULT ||
bb->result_type() == REAL_RESULT ||
bb->result_type() == DECIMAL_RESULT)) ||
(bb->result_type() == STRING_RESULT &&
(aa->result_type() == INT_RESULT ||
aa->result_type() == REAL_RESULT ||
aa->result_type() == DECIMAL_RESULT))))
return false;
// No CAST nodes are injected in comparisons with YEAR
if ((aa->data_type() == MYSQL_TYPE_YEAR &&
(bb->data_type() == MYSQL_TYPE_TIME ||
bb->data_type() == MYSQL_TYPE_TIME2)) ||
(bb->data_type() == MYSQL_TYPE_YEAR &&
(aa->data_type() == MYSQL_TYPE_TIME ||
aa->data_type() == MYSQL_TYPE_TIME2)))
return false;
// Check that both arguments are fields or functions
if (!is_non_const_field_or_function(*aa) ||
!is_non_const_field_or_function(*bb))
return false;
// If any of the arguments is not floating point number, wrap it in a CAST
if (aa->result_type() != REAL_RESULT &&
wrap_in_cast(left, MYSQL_TYPE_DOUBLE))
return true; /* purecov: inspected */
if (bb->result_type() != REAL_RESULT &&
wrap_in_cast(right, MYSQL_TYPE_DOUBLE))
return true; /* purecov: inspected */
} else if (func == &Arg_comparator::compare_datetime) {
Item *aa = (*left)->real_item();
Item *bb = (*right)->real_item();
// Check that none of the arguments are of type YEAR
if (aa->data_type() == MYSQL_TYPE_YEAR ||
bb->data_type() == MYSQL_TYPE_YEAR)
return false;
// Check that both arguments are fields or functions and that they have
// different data types
if (!is_non_const_field_or_function(*aa) ||
!is_non_const_field_or_function(*bb) ||
aa->data_type() == bb->data_type())
return false;
const bool left_is_datetime = aa->is_temporal_with_date_and_time();
const bool left_is_date = aa->is_temporal_with_date();
const bool left_is_time = aa->is_temporal_with_time();
const bool right_is_datetime = bb->is_temporal_with_date_and_time();
const bool right_is_date = bb->is_temporal_with_date();
const bool right_is_time = bb->is_temporal_with_time();
// When one of the arguments is_temporal_with_date_and_time() or one
// argument is DATE and the other one is TIME
if (left_is_datetime || right_is_datetime ||
(left_is_date && right_is_time) || (left_is_time && right_is_date)) {
if (!left_is_datetime && !right_is_datetime) {
// one is DATE, the other one is TIME so wrap both in CAST to DATETIME
return wrap_in_cast(left, MYSQL_TYPE_DATETIME) ||
wrap_in_cast(right, MYSQL_TYPE_DATETIME);
}
if (left_is_datetime && right_is_datetime) {
// E.g., DATETIME = TIMESTAMP. We allow this (we could even produce it
// ourselves by the logic below).
return false;
}
// one is DATETIME the other one is not
return left_is_datetime ? wrap_in_cast(right, MYSQL_TYPE_DATETIME)
: wrap_in_cast(left, MYSQL_TYPE_DATETIME);
}
// One of the arguments is DATE, wrap the other in CAST to DATE
if (left_is_date || right_is_date) {
return left_is_date ? wrap_in_cast(right, MYSQL_TYPE_DATE)
: wrap_in_cast(left, MYSQL_TYPE_DATE);
}
assert(left_is_time || right_is_time);
// one of the arguments is TIME, wrap the other one in CAST to TIME
return left_is_time ? wrap_in_cast(right, MYSQL_TYPE_TIME)
: wrap_in_cast(left, MYSQL_TYPE_TIME);
}
return false;
}
/*
Helper function to call from Arg_comparator::set_cmp_func()
*/
bool Arg_comparator::try_year_cmp_func(Item_result type) {
if (type == ROW_RESULT) return false;
const bool a_is_year = (*left)->data_type() == MYSQL_TYPE_YEAR;
const bool b_is_year = (*right)->data_type() == MYSQL_TYPE_YEAR;
if (!a_is_year && !b_is_year) return false;
if (a_is_year && b_is_year) {
get_value_a_func = &get_year_value;
get_value_b_func = &get_year_value;
} else if (a_is_year && (*right)->is_temporal_with_date()) {
get_value_a_func = &get_year_value;
get_value_b_func = &get_datetime_value;
} else if (b_is_year && (*left)->is_temporal_with_date()) {
get_value_b_func = &get_year_value;
get_value_a_func = &get_datetime_value;
} else
return false;
func = &Arg_comparator::compare_datetime;
set_cmp_context_for_datetime();
return true;
}
/**
Convert and cache a constant.
@param thd The current session.
@param value An item to cache
@param[out] cache_item Placeholder for the cache item
@param type Comparison type
@details
When given item is a constant and its type differs from comparison type
then cache its value to avoid type conversion of this constant on each
evaluation. In this case the value is cached and the reference to the cache
is returned.
Original value is returned otherwise.
@return cache item or original value.
*/
static Item **cache_converted_constant(THD *thd, Item **value,
Item **cache_item, Item_result type) {
// Don't need cache if doing context analysis only.
if (!(thd->lex->context_analysis_only & CONTEXT_ANALYSIS_ONLY_VIEW) &&
(*value)->const_for_execution() && type != (*value)->result_type()) {
Item_cache *cache = Item_cache::get_cache(*value, type);
cache->setup(*value);
*cache_item = cache;
return cache_item;
}
return value;
}
void Arg_comparator::set_datetime_cmp_func(Item_result_field *owner_arg,
Item **left_arg, Item **right_arg) {
owner = owner_arg;
left = left_arg;
right = right_arg;
left_cache = nullptr;
right_cache = nullptr;
func = &Arg_comparator::compare_datetime;
get_value_a_func = &get_datetime_value;
get_value_b_func = &get_datetime_value;
set_cmp_context_for_datetime();
}
/**
Retrieve correct DATETIME value from given item.
@param thd thread handle
@param item_arg item to retrieve DATETIME value from
@param warn_item item for issuing the conversion warning
@param[out] is_null true <=> the item_arg is null
Retrieves the correct DATETIME value from given item for comparison by the
compare_datetime() function.
If item's result can be compared as longlong then its int value is used
and its string value is used otherwise. Strings are always parsed and
converted to int values by the get_date_from_str() function.
This allows us to compare correctly string dates with missed insignificant
zeros. In order to compare correctly DATE and DATETIME items the result
of the former are treated as a DATETIME with zero time (00:00:00).
@returns the DATETIME value, all ones if Item is NULL
*/
longlong get_datetime_value(THD *thd, Item ***item_arg, Item **,
const Item *warn_item, bool *is_null) {
longlong value = 0;
String buf, *str = nullptr;
Item *item = **item_arg;
if (item->is_temporal() && item->data_type() != MYSQL_TYPE_YEAR) {
value = item->val_date_temporal();
*is_null = item->null_value;
} else {
str = item->val_str(&buf);
*is_null = item->null_value;
}
if (*is_null) return ~(ulonglong)0;
/*
Convert strings to the integer DATE/DATETIME representation.
Even if both dates provided in strings we can't compare them directly as
strings as there is no warranty that they are correct and do not miss
some insignificant zeros.
*/
if (str) {
bool error;
const enum_field_types f_type = warn_item->data_type();
const enum_mysql_timestamp_type t_type = f_type == MYSQL_TYPE_DATE
? MYSQL_TIMESTAMP_DATE
: MYSQL_TIMESTAMP_DATETIME;
value = (longlong)get_date_from_str(thd, str, t_type,
warn_item->item_name.ptr(), &error);
/*
If str did not contain a valid date according to the current
SQL_MODE, get_date_from_str() has already thrown a warning,
and we don't want to throw NULL on invalid date (see 5.2.6
"SQL modes" in the manual), so we're done here.
*/
}
// @todo WL#6570: restore caching of datetime values here,
// this should affect the count of warnings in mtr test
// engines.funcs.update_delete_calendar.
return value;
}
/*
Retrieves YEAR value of 19XX-00-00 00:00:00 form from given item.
SYNOPSIS
get_year_value()
item_arg [in/out] item to retrieve YEAR value from
is_null [out] true <=> the item_arg is null
DESCRIPTION
Retrieves the YEAR value of 19XX form from given item for comparison by the
compare_datetime() function.
Converts year to DATETIME of form YYYY-00-00 00:00:00 for the compatibility
with the get_datetime_value function result.
RETURN
obtained value
*/
static longlong get_year_value(THD *, Item ***item_arg, Item **, const Item *,
bool *is_null) {
longlong value = 0;
Item *item = **item_arg;
value = item->val_int();
*is_null = item->null_value;
if (*is_null) return ~(ulonglong)0;
/* Convert year to DATETIME packed format */
return year_to_longlong_datetime_packed(static_cast<long>(value));
}
/**
Compare item values as dates.
Compare items values as DATE/DATETIME for regular comparison functions.
The correct DATETIME values are obtained with help of
the get_datetime_value() function.
@returns
-1 left < right or at least one item is null
0 left == right
1 left > right
See the table:
left_is_null | 1 | 0 | 1 | 0 |
right_is_null | 1 | 1 | 0 | 0 |
result |-1 |-1 |-1 |-1/0/1|
*/
int Arg_comparator::compare_datetime() {
bool left_is_null, right_is_null;
longlong left_value, right_value;
THD *thd = current_thd;
/* Get DATE/DATETIME/TIME value of the 'left' item. */
left_value =
(*get_value_a_func)(thd, &left, &left_cache, *right, &left_is_null);
if (left_is_null) {
if (set_null) owner->null_value = true;
return -1;
}
/* Get DATE/DATETIME/TIME value of the 'right' item. */
right_value =
(*get_value_b_func)(thd, &right, &right_cache, *left, &right_is_null);
if (right_is_null) {
if (set_null) owner->null_value = true;
return -1;
}
/* Here we have two not-NULL values. */
if (set_null) owner->null_value = false;
/* Compare values. */
return left_value < right_value ? -1 : (left_value > right_value ? 1 : 0);
}
/**
Get one of the arguments to the comparator as a JSON value.
@param[in] arg pointer to the argument
@param[in,out] value buffer used for reading the JSON value
@param[in,out] tmp buffer used for converting string values to the
correct charset, if necessary
@param[out] result where to store the result
@param[in,out] scalar pointer to a location with pre-allocated memory
used for JSON scalars that are converted from
SQL scalars
@retval false on success
@retval true on failure
*/
static bool get_json_arg(Item *arg, String *value, String *tmp,
Json_wrapper *result, Json_scalar_holder **scalar) {
Json_scalar_holder *holder = nullptr;
/*
If the argument is a non-JSON type, it gets converted to a JSON
scalar. Use the pre-allocated memory passed in via the "scalar"
argument. Note, however, that geometry types are not converted
to scalars. They are converted to JSON objects by get_json_atom_wrapper().
*/
if ((arg->data_type() != MYSQL_TYPE_JSON) &&
(arg->data_type() != MYSQL_TYPE_GEOMETRY)) {
/*
If it's a constant item, and we've already read it, just return
the value that's cached in the pre-allocated memory.
*/
if (*scalar && arg->const_item()) {
*result = Json_wrapper((*scalar)->get());
/*
The DOM object lives in memory owned by the Json_scalar_holder. Tell
the wrapper that it's not the owner.
*/
result->set_alias();
return false;
}
/*
Allocate memory to hold the scalar, if we haven't already done
so. Otherwise, we reuse the previously allocated memory.
*/
if (*scalar == nullptr) *scalar = new (*THR_MALLOC) Json_scalar_holder();
holder = *scalar;
}
return get_json_atom_wrapper(&arg, 0, "<=", value, tmp, result, holder, true);
}
/**
Compare two Item objects as JSON.
If one of the arguments is NULL, and the owner is not EQUAL_FUNC,
the null_value flag of the owner will be set to true.
@return -1 if at least one of the items is NULL or if the first item is
less than the second item,
0 if the two items are equal
1 if the first item is greater than the second item.
*/
int Arg_comparator::compare_json() {
char buf[STRING_BUFFER_USUAL_SIZE];
String tmp(buf, sizeof(buf), &my_charset_bin);
// Get the JSON value in the left Item.
Json_wrapper aw;
if (get_json_arg(*left, &value1, &tmp, &aw, &json_scalar)) {
if (set_null) owner->null_value = true;
return 1;
}
const bool a_is_null = (*left)->null_value;
if (a_is_null) {
if (set_null) owner->null_value = true;
return -1;
}
// Get the JSON value in the right Item.
Json_wrapper bw;
if (get_json_arg(*right, &value1, &tmp, &bw, &json_scalar)) {
if (set_null) owner->null_value = true;
return 1;
}
const bool b_is_null = (*right)->null_value;
if (b_is_null) {
if (set_null) owner->null_value = true;
return -1;
}
if (set_null) owner->null_value = false;
return aw.compare(bw);
}
int Arg_comparator::compare_string() {
const CHARSET_INFO *cs = cmp_collation.collation;
String *res1 = eval_string_arg(cs, *left, &value1);
if (res1 == nullptr) {
if (set_null) owner->null_value = true;
return -1;
}
String *res2 = eval_string_arg(cs, *right, &value2);
if (res2 == nullptr) {
if (set_null) owner->null_value = true;
return -1;
}
if (set_null) owner->null_value = false;
const size_t l1 = res1->length();
const size_t l2 = res2->length();
// Compare the two strings
return cs->coll->strnncollsp(cs, pointer_cast<const uchar *>(res1->ptr()), l1,
pointer_cast<const uchar *>(res2->ptr()), l2);
}
/**
Compare strings byte by byte. End spaces are also compared.
@retval
<0 *left < *right
@retval
0 *right == *right
@retval
>0 *left > *right
*/
int Arg_comparator::compare_binary_string() {
String *res1, *res2;
if ((res1 = (*left)->val_str(&value1))) {
if ((res2 = (*right)->val_str(&value2))) {
if (set_null) owner->null_value = false;
const size_t len1 = res1->length();
const size_t len2 = res2->length();
const size_t min_length = min(len1, len2);
const int cmp =
min_length == 0 ? 0 : memcmp(res1->ptr(), res2->ptr(), min_length);
auto rc = cmp ? cmp : (int)(len1 - len2);
return rc;
}
}
if (set_null) owner->null_value = true;
return -1;
}
int Arg_comparator::compare_real() {
double val1, val2;
val1 = (*left)->val_real();
if (current_thd->is_error()) return 0;
if (!(*left)->null_value) {
val2 = (*right)->val_real();
if (current_thd->is_error()) return 0;
if (!(*right)->null_value) {
if (set_null) owner->null_value = false;
if (val1 < val2) return -1;
if (val1 == val2) return 0;
return 1;
}
}
if (set_null) owner->null_value = true;
return -1;
}
int Arg_comparator::compare_decimal() {
my_decimal decimal1;
my_decimal *val1 = (*left)->val_decimal(&decimal1);
if (current_thd->is_error()) return 0;
if (!(*left)->null_value) {
my_decimal decimal2;
my_decimal *val2 = (*right)->val_decimal(&decimal2);
if (current_thd->is_error()) return 0;
if (!(*right)->null_value) {
if (set_null) owner->null_value = false;
return my_decimal_cmp(val1, val2);
}
}
if (set_null) owner->null_value = true;
return -1;
}
int Arg_comparator::compare_real_fixed() {
double val1, val2;
val1 = (*left)->val_real();
if (current_thd->is_error()) return 0;
if (!(*left)->null_value) {
val2 = (*right)->val_real();
if (current_thd->is_error()) return 0;
if (!(*right)->null_value) {
if (set_null) owner->null_value = false;
if (val1 == val2 || fabs(val1 - val2) < precision) return 0;
if (val1 < val2) return -1;
return 1;
}
}
if (set_null) owner->null_value = true;
return -1;
}
int Arg_comparator::compare_int_signed() {
const longlong val1 = (*left)->val_int();
if (current_thd->is_error()) {
if (set_null) owner->null_value = true;
return 0;
}
if (!(*left)->null_value) {
const longlong val2 = (*right)->val_int();
if (current_thd->is_error()) {
if (set_null) owner->null_value = true;
return 0;
}
if (!(*right)->null_value) {
if (set_null) owner->null_value = false;
if (val1 < val2) return -1;
if (val1 == val2) return 0;
return 1;
}
}
if (set_null) owner->null_value = true;
return -1;
}
/**
Compare arguments using numeric packed temporal representation.
*/
int Arg_comparator::compare_time_packed() {
/*
Note, we cannot do this:
assert((*left)->data_type() == MYSQL_TYPE_TIME);
assert((*right)->data_type() == MYSQL_TYPE_TIME);
SELECT col_time_key FROM t1
WHERE
col_time_key != UTC_DATE()
AND
col_time_key = MAKEDATE(43, -2852);
is rewritten to:
SELECT col_time_key FROM t1
WHERE
MAKEDATE(43, -2852) != UTC_DATE()
AND
col_time_key = MAKEDATE(43, -2852);
*/
const longlong val1 = (*left)->val_time_temporal();
if (!(*left)->null_value) {
const longlong val2 = (*right)->val_time_temporal();
if (!(*right)->null_value) {
if (set_null) owner->null_value = false;
return val1 < val2 ? -1 : val1 > val2 ? 1 : 0;
}
}
if (set_null) owner->null_value = true;
return -1;
}
/**
Compare values as BIGINT UNSIGNED.
*/
int Arg_comparator::compare_int_unsigned() {
const ulonglong val1 = (*left)->val_int();
if (current_thd->is_error()) {
if (set_null) owner->null_value = true;
return 0;
}
if (!(*left)->null_value) {
const ulonglong val2 = (*right)->val_int();
if (current_thd->is_error()) {
if (set_null) owner->null_value = true;
return 0;
}
if (!(*right)->null_value) {
if (set_null) owner->null_value = false;
if (val1 < val2) return -1;
if (val1 == val2) return 0;
return 1;
}
}
if (set_null) owner->null_value = true;
return -1;
}
/**
Compare signed (*left) with unsigned (*B)
*/
int Arg_comparator::compare_int_signed_unsigned() {
const longlong sval1 = (*left)->val_int();
if (current_thd->is_error()) return 0;
if (!(*left)->null_value) {
const ulonglong uval2 = static_cast<ulonglong>((*right)->val_int());
if (current_thd->is_error()) return 0;
if (!(*right)->null_value) {
if (set_null) owner->null_value = false;
if (sval1 < 0 || (ulonglong)sval1 < uval2) return -1;
if ((ulonglong)sval1 == uval2) return 0;
return 1;
}
}
if (set_null) owner->null_value = true;
return -1;
}
/**
Compare unsigned (*left) with signed (*B)
*/
int Arg_comparator::compare_int_unsigned_signed() {
const ulonglong uval1 = static_cast<ulonglong>((*left)->val_int());
if (current_thd->is_error()) return 0;
if (!(*left)->null_value) {
const longlong sval2 = (*right)->val_int();
if (current_thd->is_error()) return 0;
if (!(*right)->null_value) {
if (set_null) owner->null_value = false;
if (sval2 < 0) return 1;
if (uval1 < (ulonglong)sval2) return -1;
if (uval1 == (ulonglong)sval2) return 0;
return 1;
}
}
if (set_null) owner->null_value = true;
return -1;
}
int Arg_comparator::compare_row() {
int res = 0;
bool was_null = false;
(*left)->bring_value();
(*right)->bring_value();
if ((*left)->null_value || (*right)->null_value) {
owner->null_value = true;
return -1;
}
const uint n = (*left)->cols();
for (uint i = 0; i < n; i++) {
res = comparators[i].compare();
/* Aggregate functions don't need special null handling. */
if (owner->null_value && owner->type() == Item::FUNC_ITEM) {
// NULL was compared
switch (((Item_func *)owner)->functype()) {
case Item_func::NE_FUNC:
break; // NE never aborts on NULL even if abort_on_null is set
case Item_func::LT_FUNC:
case Item_func::LE_FUNC:
case Item_func::GT_FUNC:
case Item_func::GE_FUNC:
return -1; // <, <=, > and >= always fail on NULL
default: // EQ_FUNC
if (down_cast<Item_bool_func2 *>(owner)->ignore_unknown())
return -1; // We do not need correct NULL returning
}
was_null = true;
owner->null_value = false;
res = 0; // continue comparison (maybe we will meet explicit difference)
} else if (res)
return res;
}
if (was_null) {
/*
There was NULL(s) in comparison in some parts, but there was no
explicit difference in other parts, so we have to return NULL.
*/
owner->null_value = true;
return -1;
}
return 0;
}
/**
Compare two argument items, or a pair of elements from two argument rows,
for NULL values.
@param a First item
@param b Second item
@param[out] result True if both items are NULL, false otherwise,
when return value is true.
@returns true if at least one of the items is NULL
*/
static bool compare_pair_for_nulls(Item *a, Item *b, bool *result) {
if (a->result_type() == ROW_RESULT) {
a->bring_value();
b->bring_value();
/*
Compare matching array elements. If only one element in a pair is NULL,
result is false, otherwise move to next pair. If the values from all pairs
are NULL, result is true.
*/
bool have_null_items = false;
for (uint i = 0; i < a->cols(); i++) {
if (compare_pair_for_nulls(a->element_index(i), b->element_index(i),
result)) {
have_null_items = true;
if (!*result) return true;
}
}
return have_null_items;
}
const bool a_null = a->is_nullable() && a->is_null();
const bool b_null = b->is_nullable() && b->is_null();
if (a_null || b_null) {
*result = a_null == b_null;
return true;
}
*result = false;
return false;
}
/**
Compare NULL values for two arguments. When called, we know that at least
one argument contains a NULL value.
@returns true if both arguments are NULL, false if one argument is NULL
*/
bool Arg_comparator::compare_null_values() {
bool result;
(void)compare_pair_for_nulls(*left, *right, &result);
return result;
}
void Item_bool_func::set_created_by_in2exists() {
m_created_by_in2exists = true;
// When a condition is created by IN to EXISTS transformation,
// it re-uses the expressions that are part of the query. As a
// result we need to increment the reference count
// for these expressions.
WalkItem(this, enum_walk::PREFIX | enum_walk::SUBQUERY, [](Item *inner_item) {
// Reference counting matters only for referenced items.
if (inner_item->type() == REF_ITEM) {
down_cast<Item_ref *>(inner_item)->ref_item()->increment_ref_count();
}
return false;
});
}
const char *Item_bool_func::bool_transform_names[10] = {"is true",
"is false",
"is null",
"is not true",
"is not false",
"is not null",
"",
"",
"",
""};
const Item::Bool_test Item_bool_func::bool_transform[10][8] = {
{BOOL_IS_TRUE, BOOL_NOT_TRUE, BOOL_ALWAYS_FALSE, BOOL_NOT_TRUE,
BOOL_IS_TRUE, BOOL_ALWAYS_TRUE, BOOL_IS_TRUE, BOOL_NOT_TRUE},
{BOOL_IS_FALSE, BOOL_NOT_FALSE, BOOL_ALWAYS_FALSE, BOOL_NOT_FALSE,
BOOL_IS_FALSE, BOOL_ALWAYS_TRUE, BOOL_IS_FALSE, BOOL_NOT_FALSE},
{BOOL_IS_UNKNOWN, BOOL_NOT_UNKNOWN, BOOL_ALWAYS_FALSE, BOOL_NOT_UNKNOWN,
BOOL_IS_UNKNOWN, BOOL_ALWAYS_TRUE, BOOL_IS_UNKNOWN, BOOL_NOT_UNKNOWN},
{BOOL_NOT_TRUE, BOOL_IS_TRUE, BOOL_ALWAYS_FALSE, BOOL_IS_TRUE,
BOOL_NOT_TRUE, BOOL_ALWAYS_TRUE, BOOL_NOT_TRUE, BOOL_IS_TRUE},
{BOOL_NOT_FALSE, BOOL_IS_FALSE, BOOL_ALWAYS_FALSE, BOOL_IS_FALSE,
BOOL_NOT_FALSE, BOOL_ALWAYS_TRUE, BOOL_NOT_FALSE, BOOL_IS_FALSE},
{BOOL_NOT_UNKNOWN, BOOL_IS_UNKNOWN, BOOL_ALWAYS_FALSE, BOOL_IS_UNKNOWN,
BOOL_NOT_UNKNOWN, BOOL_ALWAYS_TRUE, BOOL_NOT_UNKNOWN, BOOL_IS_UNKNOWN},
{BOOL_IS_TRUE, BOOL_IS_FALSE, BOOL_IS_UNKNOWN, BOOL_NOT_TRUE,
BOOL_NOT_FALSE, BOOL_NOT_UNKNOWN, BOOL_IDENTITY, BOOL_NEGATED},
{BOOL_IS_FALSE, BOOL_IS_TRUE, BOOL_IS_UNKNOWN, BOOL_NOT_FALSE,
BOOL_NOT_TRUE, BOOL_NOT_UNKNOWN, BOOL_NEGATED, BOOL_IDENTITY},
{BOOL_ALWAYS_TRUE, BOOL_ALWAYS_FALSE, BOOL_ALWAYS_FALSE, BOOL_ALWAYS_FALSE,
BOOL_ALWAYS_TRUE, BOOL_ALWAYS_TRUE, BOOL_ALWAYS_TRUE, BOOL_ALWAYS_FALSE},
{BOOL_ALWAYS_FALSE, BOOL_ALWAYS_TRUE, BOOL_ALWAYS_FALSE, BOOL_ALWAYS_TRUE,
BOOL_ALWAYS_FALSE, BOOL_ALWAYS_TRUE, BOOL_ALWAYS_FALSE, BOOL_ALWAYS_TRUE}};
bool Item_func_truth::resolve_type(THD *thd) {
set_nullable(false);
null_value = false;
return Item_bool_func::resolve_type(thd);
}
void Item_func_truth::print(const THD *thd, String *str,
enum_query_type query_type) const {
str->append('(');
args[0]->print(thd, str, query_type);
str->append(STRING_WITH_LEN(" "));
str->append(func_name());
assert(func_name()[0]);
str->append(')');
}
longlong Item_func_truth::val_int() {
const bool val = args[0]->val_bool();
if (args[0]->null_value) {
/*
NULL val IS {TRUE, FALSE} --> FALSE
NULL val IS NOT {TRUE, FALSE} --> TRUE
*/
switch (truth_test) {
case BOOL_IS_TRUE:
case BOOL_IS_FALSE:
return false;
case BOOL_NOT_TRUE:
case BOOL_NOT_FALSE:
return true;
default:
assert(false);
return false;
}
}
switch (truth_test) {
case BOOL_IS_TRUE:
case BOOL_NOT_FALSE:
return val;
case BOOL_IS_FALSE:
case BOOL_NOT_TRUE:
return !val;
default:
assert(false);
return false;
}
}
bool Item_in_optimizer::fix_left(THD *thd) {
Item *left = down_cast<Item_in_subselect *>(args[0])->left_expr;
/*
Because get_cache() depends on type of left arg, if this arg is a PS param
we must decide of its type now. We cannot wait until we know the type of
the subquery's SELECT list.
@todo: This may actually be changed later, INSPECT.
*/
if (left->propagate_type(thd, MYSQL_TYPE_VARCHAR)) return true;
assert(cache == nullptr);
cache = Item_cache::get_cache(left);
if (cache == nullptr) return true;
cache->setup(left);
used_tables_cache = left->used_tables();
/*
Propagate used tables information to the cache objects.
Since the cache objects will be used in synthesized predicates that are
added to the subquery's query expression, we need to add extra references
to them, since on removal these will be decremented twice.
*/
if (cache->cols() == 1) {
left->real_item()->increment_ref_count();
cache->set_used_tables(used_tables_cache);
} else {
uint n = cache->cols();
for (uint i = 0; i < n; i++) {
Item_cache *const element =
down_cast<Item_cache *>(cache->element_index(i));
element->set_used_tables(left->element_index(i)->used_tables());
element->real_item()->increment_ref_count();
}
}
not_null_tables_cache = left->not_null_tables();
add_accum_properties(left);
if (const_item()) cache->store(left);
return false;
}
bool Item_in_optimizer::fix_fields(THD *, Item **) {
assert(!fixed);
Item_in_subselect *subqpred = down_cast<Item_in_subselect *>(args[0]);
assert(subqpred->fixed);
if (subqpred->is_nullable()) set_nullable(true);
add_accum_properties(subqpred);
used_tables_cache |= subqpred->used_tables();
not_null_tables_cache |= subqpred->not_null_tables();
/*
not_null_tables_cache is to hold any table which, if its row is NULL,
causes the result of the complete Item to be NULL.
This can never be guaranteed, as the complete Item will return FALSE if
the subquery's result is empty.
But, if the Item's owner previously called top_level_item(), a FALSE
result is equivalent to a NULL result from the owner's POV.
A NULL value in the left argument will surely lead to a NULL or FALSE
result for the naked IN. If the complete item is:
plain IN, or IN IS TRUE, then it will return NULL or FALSE. Otherwise it
won't and we must remove the left argument from not_null_tables().
Right argument doesn't need to be handled, as
Item_subselect::not_null_tables() is always 0.
*/
if (subqpred->abort_on_null && subqpred->value_transform == BOOL_IS_TRUE) {
} else {
not_null_tables_cache &= ~subqpred->left_expr->not_null_tables();
}
fixed = true;
return false;
}
void Item_in_optimizer::fix_after_pullout(Query_block *parent_query_block,
Query_block *removed_query_block) {
used_tables_cache = get_initial_pseudo_tables();
not_null_tables_cache = 0;
args[0]->fix_after_pullout(parent_query_block, removed_query_block);
used_tables_cache |= args[0]->used_tables();
not_null_tables_cache |= args[0]->not_null_tables();
}
bool Item_in_optimizer::split_sum_func(THD *thd, Ref_item_array ref_item_array,
mem_root_deque<Item *> *fields) {
if (args[0]->split_sum_func2(thd, ref_item_array, fields, args, true)) {
return true;
}
Item **left = &down_cast<Item_in_subselect *>(args[0])->left_expr;
if ((*left)->split_sum_func2(thd, ref_item_array, fields, left, true)) {
return true;
}
return false;
}
void Item_in_optimizer::print(const THD *thd, String *str,
enum_query_type query_type) const {
str->append(func_name());
str->append('(');
down_cast<Item_in_subselect *>(args[0])->left_expr->print(thd, str,
query_type);
str->append(',');
print_args(thd, str, 0, query_type);
str->append(')');
}
/**
The implementation of optimized @<outer expression@> [NOT] IN @<subquery@>
predicates. It applies to predicates which have gone through the IN->EXISTS
transformation in in_to_exists_transformer functions; not to subquery
materialization (which has no triggered conditions).
The implementation works as follows.
For the current value of the outer expression
- If it contains only NULL values, the original (before rewrite by the
Item_in_subselect rewrite methods) inner subquery is non-correlated and
was previously executed, there is no need to re-execute it, and the
previous return value is returned.
- If it contains NULL values, check if there is a partial match for the
inner query block by evaluating it. For clarity we repeat here the
transformation previously performed on the sub-query. The expression
<tt>
( oc_1, ..., oc_n )
@<in predicate@>
( SELECT ic_1, ..., ic_n
FROM @<table@>
WHERE @<inner where@>
)
</tt>
was transformed into
<tt>
( oc_1, ..., oc_n )
\@in predicate@>
( SELECT ic_1, ..., ic_n
FROM @<table@>
WHERE @<inner where@> AND ... ( ic_k = oc_k OR ic_k IS NULL )
HAVING ... NOT ic_k IS NULL
)
</tt>
The evaluation will now proceed according to special rules set up
elsewhere. These rules include:
- The HAVING NOT @<inner column@> IS NULL conditions added by the
aforementioned rewrite methods will detect whether they evaluated (and
rejected) a NULL value and if so, will cause the subquery to evaluate
to NULL.
- The added WHERE and HAVING conditions are present only for those inner
columns that correspond to outer column that are not NULL at the moment.
- If there is an eligible index for executing the subquery, the special
access method "Full scan on NULL key" is employed which ensures that
the inner query will detect if there are NULL values resulting from the
inner query. This access method will quietly resort to table scan if it
needs to find NULL values as well.
- Under these conditions, the sub-query need only be evaluated in order to
find out whether it produced any rows.
- If it did, we know that there was a partial match since there are
NULL values in the outer row expression.
- If it did not, the result is FALSE or UNKNOWN. If at least one of the
HAVING sub-predicates rejected a NULL value corresponding to an outer
non-NULL, and hence the inner query block returns UNKNOWN upon
evaluation, there was a partial match and the result is UNKNOWN.
- If it contains no NULL values, the call is forwarded to the inner query
block.
@see Item_in_subselect::val_bool_naked()
@see Item_is_not_null_test::val_int()
*/
longlong Item_in_optimizer::val_int() {
assert(fixed);
Item_in_subselect *const subqpred = down_cast<Item_in_subselect *>(args[0]);
cache->store(subqpred->left_expr);
cache->cache_value();
if (cache->null_value) {
/*
We're evaluating
"<outer_value_list> [NOT] IN (SELECT <inner_value_list>...)"
where one or more of the outer values is NULL.
*/
if (subqpred->abort_on_null) {
/*
We're evaluating a top level item, e.g.
"<outer_value_list> IN (SELECT <inner_value_list>...)",
and in this case a NULL value in the outer_value_list means
that the result shall be NULL/FALSE (makes no difference for
top level items). The cached value is NULL, so just return
NULL.
*/
null_value = true;
} else {
/*
We're evaluating an item where a NULL value in either the
outer or inner value list does not automatically mean that we
can return NULL/FALSE. An example of such a query is
"<outer_value_list> NOT IN (SELECT <inner_value_list>...)"
where <*_list> may be a scalar or a ROW.
The result when there is at least one NULL value in <outer_value_list>
is: NULL if the SELECT evaluated over the non-NULL values produces at
least one row, FALSE otherwise
*/
bool all_left_cols_null = true;
const uint ncols = cache->cols();
/*
Turn off the predicates that are based on column compares for
which the left part is currently NULL
*/
for (uint i = 0; i < ncols; i++) {
if (cache->element_index(i)->null_value)
subqpred->set_cond_guard_var(i, false);
else
all_left_cols_null = false;
}
if (all_left_cols_null && result_for_null_param != UNKNOWN &&
!subqpred->dependent_before_in2exists()) {
/*
This subquery was originally not correlated. The IN->EXISTS
transformation may have made it correlated, but only to the left
expression. All values in the left expression are NULL, and we have
already evaluated the subquery for all NULL values: return the same
result we did last time without evaluating the subquery.
*/
null_value = result_for_null_param;
} else {
/* The subquery has to be evaluated */
(void)subqpred->val_bool_naked();
if (!subqpred->m_value)
null_value = subqpred->null_value;
else
null_value = true;
if (all_left_cols_null) result_for_null_param = null_value;
}
/* Turn all predicates back on */
for (uint i = 0; i < ncols; i++) subqpred->set_cond_guard_var(i, true);
}
cache->store(subqpred->left_expr);
return subqpred->translate(null_value, false);
}
const bool result = subqpred->val_bool_naked();
null_value = subqpred->null_value;
cache->store(subqpred->left_expr);
return subqpred->translate(null_value, result);
}
void Item_in_optimizer::cleanup() {
Item_bool_func::cleanup();
result_for_null_param = UNKNOWN;
// Restore the changes done to the cached object during execution.
// E.g. constant expressions in "left_expr" might have been
// replaced with cached items (cache_const_expr_transformer())
// which live only for one execution and these cached items
// replace the original items in "cache" during execution.
if (cache != nullptr) {
cache->store(down_cast<Item_in_subselect *>(args[0])->left_expr);
}
}
bool Item_in_optimizer::is_null() {
val_int();
return null_value;
}
void Item_in_optimizer::update_used_tables() {
Item_func::update_used_tables();
// See explanation for this logic in Item_in_optimizer::fix_fields
Item_in_subselect *subqpred = down_cast<Item_in_subselect *>(args[0]);
if (subqpred->abort_on_null && subqpred->value_transform == BOOL_IS_TRUE) {
} else {
not_null_tables_cache &= subqpred->left_expr->not_null_tables();
}
}
longlong Item_func_eq::val_int() {
assert(fixed);
const int value = cmp.compare();
return value == 0 ? 1 : 0;
}
/** Same as Item_func_eq, but NULL = NULL. */
bool Item_func_equal::resolve_type(THD *thd) {
if (Item_bool_func2::resolve_type(thd)) return true;
set_nullable(false);
null_value = false;
return false;
}
longlong Item_func_equal::val_int() {
assert(fixed);
// Perform regular equality check first:
const int value = cmp.compare();
// If comparison is not NULL, we have a result:
if (!null_value) return value == 0 ? 1 : 0;
null_value = false;
// Check NULL values for both arguments
return longlong(cmp.compare_null_values());
}
float Item_func_ne::get_filtering_effect(THD *thd, table_map filter_for_table,
table_map read_tables,
const MY_BITMAP *fields_to_ignore,
double rows_in_table) {
const Item_field *fld = contributes_to_filter(
thd, read_tables, filter_for_table, fields_to_ignore);
if (!fld) return COND_FILTER_ALLPASS;
// Find selectivity from histogram or index.
const double selectivity = [&]() {
// The index calculation might be useful for the original optimizer too,
// but we are loth to change existing plans and therefore restrict
// it to Hypergraph.
const auto index_selectivity = [&]() {
const double reverse_selectivity =
IndexSelectivityOfUnknownValue(*fld->field);
if (reverse_selectivity == kUndefinedSelectivity) {
return kUndefinedSelectivity;
} else {
// Even if all rows have the same value for 'fld', we should avoid
// returning a selectivity estimate of zero, as that can give
// a distorted view of the cost of a plan if the estimate should
// be wrong (even by a small margin).
return std::max(1.0 - reverse_selectivity,
Item_func_ne::kMinSelectivityForUnknownValue);
}
};
if (!thd->lex->using_hypergraph_optimizer()) {
return get_histogram_selectivity(
thd, *fld->field, histograms::enum_operator::NOT_EQUALS_TO, *this);
} else if (args[0]->const_item() || args[1]->const_item() ||
fld->field->key_start.is_clear_all()) {
// We prefer histograms over indexes if:
// 1) We are comparing a field to a constant, since histograms will
// give the frequency of that constant value.
// 2) If no index starts with fld->field, as index estimates will then
// be less accurate, since we do not know if that field is correlated
// with the preceding fields of the index.
const double histogram_selectivity = get_histogram_selectivity(
thd, *fld->field, histograms::enum_operator::NOT_EQUALS_TO, *this);
return histogram_selectivity == kUndefinedSelectivity
? index_selectivity()
: histogram_selectivity;
} else {
const double idx_sel = index_selectivity();
return idx_sel == kUndefinedSelectivity
? get_histogram_selectivity(
thd, *fld->field,
histograms::enum_operator::NOT_EQUALS_TO, *this)
: idx_sel;
}
}();
return selectivity == kUndefinedSelectivity
? 1.0 - fld->get_cond_filter_default_probability(
rows_in_table, COND_FILTER_EQUALITY)
: selectivity;
}
longlong Item_func_ne::val_int() {
assert(fixed);
const int value = cmp.compare();
return value != 0 && !null_value ? 1 : 0;
}
/**
Compute selectivity for field=expression and field<=>expression, where
'expression' is not Item_null.
@param thd The current thread.
@param equal The '=' or '<=>' term.
@param field The field we compare with 'expression'.
@param rows_in_table Number of rows in the table of 'field'.
@returns Selectivity estimate.
*/
static double GetEqualSelectivity(THD *thd, Item_eq_base *equal,
const Item_field &field,
double rows_in_table) {
assert(equal->argument_count() == 2);
assert(std::none_of(
equal->arguments(), equal->arguments() + equal->argument_count(),
[](const Item *item) { return item->type() == Item::NULL_ITEM; }));
const double selectivity = [&]() {
// The index calculation might be useful for the original optimizer too,
// but we are loth to change existing plans and therefore restrict
// it to Hypergraph.
if (!thd->lex->using_hypergraph_optimizer()) {
return get_histogram_selectivity(
thd, *field.field, histograms::enum_operator::EQUALS_TO, *equal);
} else if (equal->arguments()[0]->const_item() ||
equal->arguments()[1]->const_item() ||
field.field->key_start.is_clear_all()) {
// We prefer histograms over indexes if:
// 1) We are comparing a field to a constant, since histograms will
// give the frequency of that constant value.
// 2) If no index starts with field.field, as index estimates will then
// be less accurate, since we do not know if that field is correlated
// with the preceding fields of the index.
const double histogram_selectivity = get_histogram_selectivity(
thd, *field.field, histograms::enum_operator::EQUALS_TO, *equal);
return histogram_selectivity == kUndefinedSelectivity
? IndexSelectivityOfUnknownValue(*field.field)
: histogram_selectivity;
} else {
const double index_selectivity =
IndexSelectivityOfUnknownValue(*field.field);
return index_selectivity == kUndefinedSelectivity
? get_histogram_selectivity(
thd, *field.field, histograms::enum_operator::EQUALS_TO,
*equal)
: index_selectivity;
}
}();
return selectivity == kUndefinedSelectivity
? field.get_cond_filter_default_probability(rows_in_table,
COND_FILTER_EQUALITY)
: selectivity;
}
float Item_func_equal::get_filtering_effect(THD *thd,
table_map filter_for_table,
table_map read_tables,
const MY_BITMAP *fields_to_ignore,
double rows_in_table) {
const Item_field *fld = contributes_to_filter(
thd, read_tables, filter_for_table, fields_to_ignore);
if (!fld) return COND_FILTER_ALLPASS;
for (int i : {0, 1}) {
if (arguments()[i]->type() == NULL_ITEM) {
if (!fld->field->is_nullable()) {
return 0.0;
}
const Item_func *is_null =
new (thd->mem_root) Item_func_isnull(arguments()[(i + 1) % 2]);
const double histogram_selectivity = get_histogram_selectivity(
thd, *fld->field, histograms::enum_operator::IS_NULL, *is_null);
if (histogram_selectivity >= 0.0) {
return histogram_selectivity;
} else {
return fld->get_cond_filter_default_probability(rows_in_table,
COND_FILTER_EQUALITY);
}
}
}
return GetEqualSelectivity(thd, this, *fld, rows_in_table);
}
float Item_func_inequality::get_filtering_effect(
THD *thd, table_map filter_for_table, table_map read_tables,
const MY_BITMAP *fields_to_ignore, double rows_in_table) {
// For comparing MATCH(...), generally reuse the same selectivity as for
// MATCH(...), which is generally COND_FILTER_BETWEEN. This is wrong
// in a number of cases (the equivalence only holds for MATCH(...) > 0
// or 0 < MATCH(...)) but usually less wrong than the default down below,
// which is COND_FILTER_ALLPASS (1.0).
//
// Ideally, of course, we should have had a real estimation of MATCH(...)
// selectivity in the form of some sort of histogram, and then read out
// that histogram here. However, that is a larger job.
if (is_function_of_type(args[0], Item_func::FT_FUNC) &&
args[1]->const_item()) {
return args[0]->get_filtering_effect(thd, filter_for_table, read_tables,
fields_to_ignore, rows_in_table);
}
if (is_function_of_type(args[1], Item_func::FT_FUNC) &&
args[0]->const_item()) {
return args[1]->get_filtering_effect(thd, filter_for_table, read_tables,
fields_to_ignore, rows_in_table);
}
const Item_field *fld = contributes_to_filter(
thd, read_tables, filter_for_table, fields_to_ignore);
if (!fld) return COND_FILTER_ALLPASS;
const histograms::enum_operator comp_op = [&]() {
switch (functype()) {
case GT_FUNC:
return histograms::enum_operator::GREATER_THAN;
case LT_FUNC:
return histograms::enum_operator::LESS_THAN;
case GE_FUNC:
return histograms::enum_operator::GREATER_THAN_OR_EQUAL;
case LE_FUNC:
return histograms::enum_operator::LESS_THAN_OR_EQUAL;
default:
assert(false);
return histograms::enum_operator::GREATER_THAN;
};
}();
const double selectivity =
get_histogram_selectivity(thd, *fld->field, comp_op, *this);
return selectivity == kUndefinedSelectivity
? fld->get_cond_filter_default_probability(rows_in_table,
COND_FILTER_INEQUALITY)
: selectivity;
}
longlong Item_func_ge::val_int() {
assert(fixed);
const int value = cmp.compare();
return value >= 0 ? 1 : 0;
}
longlong Item_func_gt::val_int() {
assert(fixed);
const int value = cmp.compare();
return value > 0 ? 1 : 0;
}
longlong Item_func_le::val_int() {
assert(fixed);
const int value = cmp.compare();
return value <= 0 && !null_value ? 1 : 0;
}
longlong Item_func_reject_if::val_int() {
const longlong result = args[0]->val_int();
if (result == 1) {
my_error(ER_SUBQUERY_NO_1_ROW, MYF(0));
}
return !result;
}
float Item_func_reject_if::get_filtering_effect(
THD *thd, table_map filter_for_table, table_map read_tables,
const MY_BITMAP *fields_to_ignore, double rows_in_table) {
return args[0]->get_filtering_effect(thd, filter_for_table, read_tables,
fields_to_ignore, rows_in_table);
}
longlong Item_func_lt::val_int() {
assert(fixed);
const int value = cmp.compare();
return value < 0 && !null_value ? 1 : 0;
}
longlong Item_func_strcmp::val_int() {
assert(fixed);
const CHARSET_INFO *cs = cmp.cmp_collation.collation;
String *a = eval_string_arg(cs, args[0], &cmp.value1);
if (a == nullptr) {
if (current_thd->is_error()) return error_int();
null_value = true;
return 0;
}
String *b = eval_string_arg(cs, args[1], &cmp.value2);
if (b == nullptr) {
if (current_thd->is_error()) return error_int();
null_value = true;
return 0;
}
const int value = sortcmp(a, b, cs);
null_value = false;
return value == 0 ? 0 : value < 0 ? -1 : 1;
}
bool Item_func_opt_neg::eq(const Item *item, bool binary_cmp) const {
/* Assume we don't have rtti */
if (this == item) return true;
if (item->type() != FUNC_ITEM) return false;
const Item_func *item_func = down_cast<const Item_func *>(item);
if (arg_count != item_func->arg_count || functype() != item_func->functype())
return false;
if (negated != down_cast<const Item_func_opt_neg *>(item_func)->negated)
return false;
return AllItemsAreEqual(args, item_func->arguments(), arg_count, binary_cmp);
}
bool Item_func_interval::do_itemize(Parse_context *pc, Item **res) {
if (skip_itemize(res)) return false;
if (row == nullptr || // OOM in constructor
super::do_itemize(pc, res))
return true;
assert(row == args[0]); // row->itemize() is not needed
return false;
}
Item_row *Item_func_interval::alloc_row(const POS &pos, MEM_ROOT *mem_root,
Item *expr1, Item *expr2,
PT_item_list *opt_expr_list) {
mem_root_deque<Item *> *list =
opt_expr_list ? &opt_expr_list->value
: new (mem_root) mem_root_deque<Item *>(mem_root);
if (list == nullptr) return nullptr;
list->push_front(expr2);
Item_row *tmprow = new (mem_root) Item_row(pos, expr1, *list);
return tmprow;
}
bool Item_func_interval::resolve_type(THD *thd) {
const uint rows = row->cols();
// The number of columns in one argument is limited to one
for (uint i = 0; i < rows; i++) {
if (row->element_index(i)->check_cols(1)) return true;
if (row->element_index(i)->propagate_type(thd, MYSQL_TYPE_LONGLONG))
return true;
}
use_decimal_comparison =
((row->element_index(0)->result_type() == DECIMAL_RESULT) ||
(row->element_index(0)->result_type() == INT_RESULT));
if (rows > 8) {
bool not_null_consts = true;
for (uint i = 1; not_null_consts && i < rows; i++) {
Item *el = row->element_index(i);
not_null_consts = el->const_item() && !el->is_null();
}
if (not_null_consts) {
intervals = static_cast<interval_range *>(
(*THR_MALLOC)->Alloc(sizeof(interval_range) * (rows - 1)));
if (intervals == nullptr) return true;
if (use_decimal_comparison) {
for (uint i = 1; i < rows; i++) {
Item *el = row->element_index(i);
interval_range *range = intervals + (i - 1);
if ((el->result_type() == DECIMAL_RESULT) ||
(el->result_type() == INT_RESULT)) {
range->type = DECIMAL_RESULT;
range->dec.init();
my_decimal *dec = el->val_decimal(&range->dec);
if (dec != &range->dec) {
range->dec = *dec;
}
} else {
range->type = REAL_RESULT;
range->dbl = el->val_real();
}
}
} else {
for (uint i = 1; i < rows; i++) {
intervals[i - 1].dbl = row->element_index(i)->val_real();
}
}
}
}
set_nullable(false);
max_length = 2;
used_tables_cache |= row->used_tables();
not_null_tables_cache = row->not_null_tables();
add_accum_properties(row);
return false;
}
void Item_func_interval::update_used_tables() {
Item_func::update_used_tables();
not_null_tables_cache = row->not_null_tables();
}
/**
Appends function name and arguments list to the String str.
@note
Arguments of INTERVAL function are stored in "Item_row" object. Function
print_args calls print function of "Item_row" class. Item_row::print
function append "(", "argument_list" and ")" to String str.
@param thd Thread handle
@param [in,out] str String to which the func_name and argument list
should be appended.
@param query_type Query type
*/
void Item_func_interval::print(const THD *thd, String *str,
enum_query_type query_type) const {
str->append(func_name());
print_args(thd, str, 0, query_type);
}
/**
Execute Item_func_interval().
@note
If we are doing a decimal comparison, we are evaluating the first
item twice.
@return
- -1 if null value,
- 0 if lower than lowest
- 1 - arg_count-1 if between args[n] and args[n+1]
- arg_count if higher than biggest argument
*/
longlong Item_func_interval::val_int() {
assert(fixed);
double value;
my_decimal dec_buf, *dec = nullptr;
uint i;
if (use_decimal_comparison) {
dec = row->element_index(0)->val_decimal(&dec_buf);
if (row->element_index(0)->null_value) return -1;
my_decimal2double(E_DEC_FATAL_ERROR, dec, &value);
} else {
value = row->element_index(0)->val_real();
if (row->element_index(0)->null_value) return -1;
}
if (intervals) { // Use binary search to find interval
uint start, end;
start = 0;
end = row->cols() - 2;
while (start != end) {
const uint mid = (start + end + 1) / 2;
interval_range *range = intervals + mid;
bool cmp_result;
/*
The values in the range interval may have different types,
Only do a decimal comparison of the first argument is a decimal
and we are comparing against a decimal
*/
if (dec && range->type == DECIMAL_RESULT)
cmp_result = my_decimal_cmp(&range->dec, dec) <= 0;
else
cmp_result = (range->dbl <= value);
if (cmp_result)
start = mid;
else
end = mid - 1;
}
interval_range *range = intervals + start;
return ((dec && range->type == DECIMAL_RESULT)
? my_decimal_cmp(dec, &range->dec) < 0
: value < range->dbl)
? 0
: start + 1;
}
for (i = 1; i < row->cols(); i++) {
Item *el = row->element_index(i);
if (use_decimal_comparison && ((el->result_type() == DECIMAL_RESULT) ||
(el->result_type() == INT_RESULT))) {
my_decimal e_dec_buf, *e_dec = el->val_decimal(&e_dec_buf);
/* Skip NULL ranges. */
if (el->null_value) continue;
if (my_decimal_cmp(e_dec, dec) > 0) return i - 1;
} else {
const double val = el->val_real();
/* Skip NULL ranges. */
if (el->null_value) continue;
if (val > value) return i - 1;
}
}
return i - 1;
}
/**
Perform context analysis of a BETWEEN item tree.
This function performs context analysis (name resolution) and calculates
various attributes of the item tree with Item_func_between as its root.
The function saves in ref the pointer to the item or to a newly created
item that is considered as a replacement for the original one.
@param thd reference to the global context of the query thread
@param ref pointer to Item* variable where pointer to resulting "fixed"
item is to be assigned
@note
Let T0(e)/T1(e) be the value of not_null_tables(e) when e is used on
a predicate/function level. Then it's easy to show that:
@verbatim
T0(e BETWEEN e1 AND e2) = union(T1(e),T1(e1),T1(e2))
T1(e BETWEEN e1 AND e2) = union(T1(e),intersection(T1(e1),T1(e2)))
T0(e NOT BETWEEN e1 AND e2) = union(T1(e),intersection(T1(e1),T1(e2)))
T1(e NOT BETWEEN e1 AND e2) = union(T1(e),intersection(T1(e1),T1(e2)))
@endverbatim
@retval
0 ok
@retval
1 got error
*/
bool Item_func_between::fix_fields(THD *thd, Item **ref) {
if (Item_func_opt_neg::fix_fields(thd, ref)) return true;
thd->lex->current_query_block()->between_count++;
update_not_null_tables();
// if 'high' and 'low' are same, convert this to a _eq function
if (!negated && args[1]->const_item() && args[2]->const_item() &&
args[1]->eq(args[2], true)) {
Item *item = new (thd->mem_root) Item_func_eq(args[0], args[1]);
if (item == nullptr) return true;
item->item_name = item_name;
if (item->fix_fields(thd, ref)) return true;
*ref = item;
}
return false;
}
void Item_func_between::fix_after_pullout(Query_block *parent_query_block,
Query_block *removed_query_block) {
Item_func_opt_neg::fix_after_pullout(parent_query_block, removed_query_block);
update_not_null_tables();
}
bool Item_func_between::resolve_type(THD *thd) {
max_length = 1;
int datetime_items_found = 0;
int time_items_found = 0;
compare_as_dates_with_strings = false;
compare_as_temporal_times = compare_as_temporal_dates = false;
// All three arguments are needed for type resolving
assert(args[0] && args[1] && args[2]);
if (Item_func_opt_neg::resolve_type(thd)) return true;
cmp_type = agg_cmp_type(args, 3);
if (cmp_type == STRING_RESULT &&
agg_arg_charsets_for_comparison(cmp_collation, args, 3))
return true;
/*
See comments for the code block doing similar checks in
Item_bool_func2::resolve_type().
*/
if (reject_geometry_args(arg_count, args, this)) return true;
/*
JSON values will be compared as strings, and not with the JSON
comparator as one might expect. Raise a warning if one of the
arguments is JSON.
*/
unsupported_json_comparison(arg_count, args,
"comparison of JSON in the BETWEEN operator");
/*
Detect the comparison of DATE/DATETIME items.
At least one of items should be a DATE/DATETIME item and other items
should return the STRING result.
*/
if (cmp_type == STRING_RESULT) {
for (int i = 0; i < 3; i++) {
if (args[i]->is_temporal_with_date())
datetime_items_found++;
else if (args[i]->data_type() == MYSQL_TYPE_TIME)
time_items_found++;
}
}
if (datetime_items_found + time_items_found == 3) {
if (time_items_found == 3) {
// All items are TIME
cmp_type = INT_RESULT;
compare_as_temporal_times = true;
} else {
/*
There is at least one DATE or DATETIME item,
all other items are DATE, DATETIME or TIME.
*/
cmp_type = INT_RESULT;
compare_as_temporal_dates = true;
}
} else if (datetime_items_found > 0) {
/*
There is at least one DATE or DATETIME item.
All other items are DATE, DATETIME or strings.
*/
compare_as_dates_with_strings = true;
ge_cmp.set_datetime_cmp_func(this, args, args + 1);
le_cmp.set_datetime_cmp_func(this, args, args + 2);
} else if (args[0]->real_item()->type() == FIELD_ITEM &&
thd->lex->sql_command != SQLCOM_CREATE_VIEW &&
thd->lex->sql_command != SQLCOM_SHOW_CREATE) {
Item_field *field_item = (Item_field *)(args[0]->real_item());
if (field_item->field->can_be_compared_as_longlong()) {
/*
The following can't be recoded with || as convert_constant_item
changes the argument
*/
bool cvt_arg1, cvt_arg2;
if (convert_constant_item(thd, field_item, &args[1], &cvt_arg1))
return true;
if (convert_constant_item(thd, field_item, &args[2], &cvt_arg2))
return true;
if (args[0]->is_temporal()) { // special handling of date/time etc.
if (cvt_arg1 || cvt_arg2) cmp_type = INT_RESULT;
} else {
if (cvt_arg1 && cvt_arg2) cmp_type = INT_RESULT;
}
if (args[0]->is_temporal() && args[1]->is_temporal() &&
args[2]->is_temporal() && args[0]->data_type() != MYSQL_TYPE_YEAR &&
args[1]->data_type() != MYSQL_TYPE_YEAR &&
args[2]->data_type() != MYSQL_TYPE_YEAR) {
/*
An expression:
time_or_datetime_field
BETWEEN const_number_or_time_or_datetime_expr1
AND const_number_or_time_or_datetime_expr2
was rewritten to:
time_field
BETWEEN Item_time_with_ref1
AND Item_time_with_ref2
or
datetime_field
BETWEEN Item_datetime_with_ref1
AND Item_datetime_with_ref2
*/
if (field_item->data_type() == MYSQL_TYPE_TIME)
compare_as_temporal_times = true;
else if (field_item->is_temporal_with_date())
compare_as_temporal_dates = true;
}
}
}
return false;
}
void Item_func_between::update_used_tables() {
Item_func::update_used_tables();
update_not_null_tables();
}
float Item_func_between::get_filtering_effect(THD *thd,
table_map filter_for_table,
table_map read_tables,
const MY_BITMAP *fields_to_ignore,
double rows_in_table) {
const Item_field *fld = contributes_to_filter(
thd, read_tables, filter_for_table, fields_to_ignore);
if (!fld) return COND_FILTER_ALLPASS;
const histograms::enum_operator op =
(negated ? histograms::enum_operator::NOT_BETWEEN
: histograms::enum_operator::BETWEEN);
const double selectivity =
get_histogram_selectivity(thd, *fld->field, op, *this);
if (selectivity == kUndefinedSelectivity) {
const float filter = fld->get_cond_filter_default_probability(
rows_in_table, COND_FILTER_BETWEEN);
return negated ? 1.0f - filter : filter;
} else {
return selectivity;
}
}
/**
A helper function for Item_func_between::val_int() to avoid
over/underflow when comparing large values.
@tparam LLorULL ulonglong or longlong
@param compare_as_temporal_dates copy of Item_func_between member variable
@param compare_as_temporal_times copy of Item_func_between member variable
@param negated copy of Item_func_between member variable
@param args copy of Item_func_between member variable
@param [out] null_value set to true if result is not true/false
@retval true if: args[1] <= args[0] <= args[2]
*/
template <typename LLorULL>
static inline longlong compare_between_int_result(
bool compare_as_temporal_dates, bool compare_as_temporal_times,
bool negated, Item **args, bool *null_value) {
{
LLorULL a, b, value;
value = compare_as_temporal_times ? args[0]->val_time_temporal()
: compare_as_temporal_dates ? args[0]->val_date_temporal()
: args[0]->val_int();
if ((*null_value = args[0]->null_value)) return 0; /* purecov: inspected */
if (compare_as_temporal_times) {
a = args[1]->val_time_temporal();
b = args[2]->val_time_temporal();
} else if (compare_as_temporal_dates) {
a = args[1]->val_date_temporal();
b = args[2]->val_date_temporal();
} else {
a = args[1]->val_int();
b = args[2]->val_int();
}
if (std::is_unsigned<LLorULL>::value) {
/*
Comparing as unsigned.
value BETWEEN <some negative number> AND <some number>
rewritten to
value BETWEEN 0 AND <some number>
*/
if (!args[1]->unsigned_flag && static_cast<longlong>(a) < 0) a = 0;
/*
Comparing as unsigned.
value BETWEEN <some number> AND <some negative number>
rewritten to
1 BETWEEN <some number> AND 0
*/
if (!args[2]->unsigned_flag && static_cast<longlong>(b) < 0) {
b = 0;
value = 1;
}
} else {
// Comparing as signed, but a is unsigned and > LLONG_MAX.
if (args[1]->unsigned_flag && static_cast<longlong>(a) < 0) {
if (value < 0) {
/*
value BETWEEN <large number> AND b
rewritten to
value BETWEEN 0 AND b
*/
a = 0;
} else {
/*
value BETWEEN <large number> AND b
rewritten to
value BETWEEN LLONG_MAX AND b
*/
a = LLONG_MAX;
// rewrite to: (value-1) BETWEEN LLONG_MAX AND b
if (value == LLONG_MAX) value -= 1;
}
}
// Comparing as signed, but b is unsigned, and really large
if (args[2]->unsigned_flag && static_cast<longlong>(b) < 0) b = LLONG_MAX;
}
if (!args[1]->null_value && !args[2]->null_value)
return (longlong)((value >= a && value <= b) != negated);
if (args[1]->null_value && args[2]->null_value)
*null_value = true;
else if (args[1]->null_value) {
*null_value = value <= b; // not null if false range.
} else {
*null_value = value >= a;
}
return value;
}
}
longlong Item_func_between::val_int() { // ANSI BETWEEN
assert(fixed);
THD *thd = current_thd;
if (compare_as_dates_with_strings) {
const int ge_res = ge_cmp.compare();
if ((null_value = args[0]->null_value)) return 0;
const int le_res = le_cmp.compare();
if (!args[1]->null_value && !args[2]->null_value)
return (longlong)((ge_res >= 0 && le_res <= 0) != negated);
else if (args[1]->null_value) {
null_value = le_res <= 0; // not null if false range.
} else {
null_value = ge_res >= 0;
}
} else if (cmp_type == STRING_RESULT) {
const CHARSET_INFO *cs = cmp_collation.collation;
String *value = eval_string_arg(cs, args[0], &value0);
null_value = args[0]->null_value;
if (value == nullptr) {
null_value = true;
return 0;
}
String *a = eval_string_arg(cs, args[1], &value1);
if (thd->is_error()) {
return error_int();
}
String *b = eval_string_arg(cs, args[2], &value2);
if (thd->is_error()) {
return error_int();
}
if (!args[1]->null_value && !args[2]->null_value)
return (longlong)((sortcmp(value, a, cmp_collation.collation) >= 0 &&
sortcmp(value, b, cmp_collation.collation) <= 0) !=
negated);
if (args[1]->null_value && args[2]->null_value)
null_value = true;
else if (args[1]->null_value) {
// Set to not null if false range.
null_value = sortcmp(value, b, cmp_collation.collation) <= 0;
} else {
// Set to not null if false range.
null_value = sortcmp(value, a, cmp_collation.collation) >= 0;
}
} else if (cmp_type == INT_RESULT) {
longlong value;
if (args[0]->unsigned_flag)
value = compare_between_int_result<ulonglong>(compare_as_temporal_dates,
compare_as_temporal_times,
negated, args, &null_value);
else
value = compare_between_int_result<longlong>(compare_as_temporal_dates,
compare_as_temporal_times,
negated, args, &null_value);
if (args[0]->null_value) return 0; /* purecov: inspected */
if (!args[1]->null_value && !args[2]->null_value) return value;
} else if (cmp_type == DECIMAL_RESULT) {
my_decimal dec_buf, *dec = args[0]->val_decimal(&dec_buf), a_buf, *a_dec,
b_buf, *b_dec;
if ((null_value = args[0]->null_value)) return 0; /* purecov: inspected */
a_dec = args[1]->val_decimal(&a_buf);
b_dec = args[2]->val_decimal(&b_buf);
if (!args[1]->null_value && !args[2]->null_value)
return (longlong)((my_decimal_cmp(dec, a_dec) >= 0 &&
my_decimal_cmp(dec, b_dec) <= 0) != negated);
if (args[1]->null_value && args[2]->null_value)
null_value = true;
else if (args[1]->null_value)
null_value = (my_decimal_cmp(dec, b_dec) <= 0);
else
null_value = (my_decimal_cmp(dec, a_dec) >= 0);
} else {
const double value = args[0]->val_real();
double a, b;
if (thd->is_error()) return false;
if ((null_value = args[0]->null_value)) return 0; /* purecov: inspected */
a = args[1]->val_real();
if (thd->is_error()) return false;
b = args[2]->val_real();
if (thd->is_error()) return false;
if (!args[1]->null_value && !args[2]->null_value)
return (longlong)((value >= a && value <= b) != negated);
if (args[1]->null_value && args[2]->null_value)
null_value = true;
else if (args[1]->null_value) {
null_value = value <= b; // not null if false range.
} else {
null_value = value >= a;
}
}
return (longlong)(!null_value && negated);
}
void Item_func_between::print(const THD *thd, String *str,
enum_query_type query_type) const {
str->append('(');
args[0]->print(thd, str, query_type);
if (negated) str->append(STRING_WITH_LEN(" not"));
str->append(STRING_WITH_LEN(" between "));
args[1]->print(thd, str, query_type);
str->append(STRING_WITH_LEN(" and "));
args[2]->print(thd, str, query_type);
str->append(')');
}
Field *Item_func_ifnull::tmp_table_field(TABLE *table) {
return tmp_table_field_from_field_type(table, false);
}
double Item_func_ifnull::real_op() {
assert(fixed);
double value = args[0]->val_real();
if (current_thd->is_error()) return error_real();
if (!args[0]->null_value) {
null_value = false;
return value;
}
value = args[1]->val_real();
if (current_thd->is_error()) return error_real();
if ((null_value = args[1]->null_value)) return 0.0;
return value;
}
longlong Item_func_ifnull::int_op() {
assert(fixed);
longlong value = args[0]->val_int();
if (current_thd->is_error()) return error_int();
if (!args[0]->null_value) {
null_value = false;
return value;
}
value = args[1]->val_int();
if (current_thd->is_error()) return error_int();
if ((null_value = args[1]->null_value)) return 0;
return value;
}
my_decimal *Item_func_ifnull::decimal_op(my_decimal *decimal_value) {
assert(fixed);
my_decimal *value = args[0]->val_decimal(decimal_value);
if (current_thd->is_error()) return error_decimal(decimal_value);
if (!args[0]->null_value) {
null_value = false;
return value;
}
value = args[1]->val_decimal(decimal_value);
if (current_thd->is_error()) return error_decimal(decimal_value);
if ((null_value = args[1]->null_value)) return nullptr;
return value;
}
bool Item_func_ifnull::val_json(Json_wrapper *result) {
null_value = false;
bool has_value;
if (json_value(args[0], result, &has_value)) return error_json();
assert(!current_thd->is_error() && has_value);
if (!args[0]->null_value) return false;
if (json_value(args[1], result, &has_value)) return error_json();
assert(!current_thd->is_error() && has_value);
null_value = args[1]->null_value;
return false;
}
bool Item_func_ifnull::date_op(MYSQL_TIME *ltime, my_time_flags_t fuzzydate) {
assert(fixed);
if (!args[0]->get_date(ltime, fuzzydate)) return (null_value = false);
return (null_value = args[1]->get_date(ltime, fuzzydate));
}
bool Item_func_ifnull::time_op(MYSQL_TIME *ltime) {
assert(fixed);
if (!args[0]->get_time(ltime)) return (null_value = false);
return (null_value = args[1]->get_time(ltime));
}
String *Item_func_ifnull::str_op(String *str) {
assert(fixed);
String *res = args[0]->val_str(str);
if (current_thd->is_error()) return error_str();
if (!args[0]->null_value) {
null_value = false;
res->set_charset(collation.collation);
return res;
}
res = args[1]->val_str(str);
if (current_thd->is_error()) return error_str();
if ((null_value = args[1]->null_value)) return nullptr;
res->set_charset(collation.collation);
return res;
}
/**
Perform context analysis of an IF item tree.
This function performs context analysis (name resolution) and calculates
various attributes of the item tree with Item_func_if as its root.
The function saves in ref the pointer to the item or to a newly created
item that is considered as a replacement for the original one.
@param thd reference to the global context of the query thread
@param ref pointer to Item* variable where pointer to resulting "fixed"
item is to be assigned
@note
Let T0(e)/T1(e) be the value of not_null_tables(e) when e is used on
a predicate/function level. Then it's easy to show that:
@verbatim
T0(IF(e,e1,e2) = T1(IF(e,e1,e2))
T1(IF(e,e1,e2)) = intersection(T1(e1),T1(e2))
@endverbatim
@retval
0 ok
@retval
1 got error
*/
bool Item_func_if::fix_fields(THD *thd, Item **ref) {
assert(!fixed);
args[0]->apply_is_true();
if (Item_func::fix_fields(thd, ref)) return true;
update_not_null_tables();
return false;
}
void Item_func_if::fix_after_pullout(Query_block *parent_query_block,
Query_block *removed_query_block) {
Item_func::fix_after_pullout(parent_query_block, removed_query_block);
update_not_null_tables();
}
void Item_func_if::update_used_tables() {
Item_func::update_used_tables();
update_not_null_tables();
}
bool Item_func_if::resolve_type(THD *thd) {
// Assign type to the condition argument, if necessary
if (param_type_is_default(thd, 0, 1, MYSQL_TYPE_LONGLONG)) return true;
/*
If none of the return arguments have type, type of this operator cannot
be determined yet
*/
if (args[1]->data_type() == MYSQL_TYPE_INVALID &&
args[2]->data_type() == MYSQL_TYPE_INVALID)
return false;
return resolve_type_inner(thd);
}
bool Item_func_if::resolve_type_inner(THD *thd) {
args++;
arg_count--;
if (param_type_uses_non_param(thd)) return true;
args--;
arg_count++;
set_nullable(args[1]->is_nullable() || args[2]->is_nullable());
if (aggregate_type(func_name(), args + 1, 2)) return true;
cached_result_type = Field::result_merge_type(data_type());
return false;
}
TYPELIB *Item_func_if::get_typelib() const {
if (data_type() != MYSQL_TYPE_ENUM && data_type() != MYSQL_TYPE_SET) {
return nullptr;
}
assert((args[1]->data_type() == MYSQL_TYPE_NULL) ^
(args[2]->data_type() == MYSQL_TYPE_NULL));
TYPELIB *typelib = args[1]->data_type() != MYSQL_TYPE_NULL
? args[1]->get_typelib()
: args[2]->get_typelib();
assert(typelib != nullptr);
return typelib;
}
double Item_func_if::val_real() {
assert(fixed);
Item *arg = args[0]->val_bool() ? args[1] : args[2];
if (current_thd->is_error()) return error_real();
const double value = arg->val_real();
null_value = arg->null_value;
return value;
}
longlong Item_func_if::val_int() {
assert(fixed);
Item *arg = args[0]->val_bool() ? args[1] : args[2];
if (current_thd->is_error()) return error_int();
const longlong value = arg->val_int();
null_value = arg->null_value;
return value;
}
String *Item_func_if::val_str(String *str) {
assert(fixed);
switch (data_type()) {
case MYSQL_TYPE_DATETIME:
case MYSQL_TYPE_TIMESTAMP:
return val_string_from_datetime(str);
case MYSQL_TYPE_DATE:
return val_string_from_date(str);
case MYSQL_TYPE_TIME:
return val_string_from_time(str);
default: {
Item *item = args[0]->val_bool() ? args[1] : args[2];
if (current_thd->is_error()) return error_str();
String *res;
if ((res = item->val_str(str))) {
res->set_charset(collation.collation);
null_value = false;
return res;
}
}
}
null_value = true;
return nullptr;
}
my_decimal *Item_func_if::val_decimal(my_decimal *decimal_value) {
assert(fixed);
Item *arg = args[0]->val_bool() ? args[1] : args[2];
if (current_thd->is_error()) return error_decimal(decimal_value);
my_decimal *value = arg->val_decimal(decimal_value);
null_value = arg->null_value;
return value;
}
bool Item_func_if::val_json(Json_wrapper *wr) {
assert(fixed);
Item *arg = args[0]->val_bool() ? args[1] : args[2];
if (current_thd->is_error()) return error_json();
bool has_value;
const bool ok = json_value(arg, wr, &has_value);
assert(has_value);
null_value = arg->null_value;
return ok;
}
bool Item_func_if::get_date(MYSQL_TIME *ltime, my_time_flags_t fuzzydate) {
assert(fixed);
Item *arg = args[0]->val_bool() ? args[1] : args[2];
if (arg->get_date(ltime, fuzzydate)) return error_date();
null_value = arg->null_value;
return false;
}
bool Item_func_if::get_time(MYSQL_TIME *ltime) {
assert(fixed);
Item *arg = args[0]->val_bool() ? args[1] : args[2];
if (arg->get_time(ltime)) return error_time();
null_value = arg->null_value;
return false;
}
bool Item_func_nullif::resolve_type(THD *thd) {
// If no arguments have a type, type of this operator cannot be determined yet
if (args[0]->data_type() == MYSQL_TYPE_INVALID &&
args[1]->data_type() == MYSQL_TYPE_INVALID) {
/*
Due to inheritance from Item_bool_func2, data_type() is LONGLONG.
Ensure propagate_type() is called for this class:
*/
set_data_type(MYSQL_TYPE_INVALID);
return false;
}
return resolve_type_inner(thd);
}
bool Item_func_nullif::resolve_type_inner(THD *thd) {
if (Item_bool_func2::resolve_type(thd)) return true;
set_nullable(true);
set_data_type_from_item(args[0]);
cached_result_type = args[0]->result_type();
// This class does not implement temporal data types
if (is_temporal()) {
set_data_type_string(args[0]->max_length);
if (agg_arg_charsets_for_comparison(cmp.cmp_collation, args, arg_count))
return true;
cached_result_type = STRING_RESULT;
}
return false;
}
TYPELIB *Item_func_nullif::get_typelib() const {
return args[0]->get_typelib();
}
/**
@note
Note that we have to evaluate the first argument twice as the compare
may have been done with a different type than return value
@return
NULL if arguments are equal
@return
the first argument if not equal
*/
double Item_func_nullif::val_real() {
assert(fixed);
double value;
if (!cmp.compare()) {
null_value = true;
return 0.0;
}
value = args[0]->val_real();
null_value = args[0]->null_value;
return value;
}
longlong Item_func_nullif::val_int() {
assert(fixed);
longlong value;
if (!cmp.compare()) {
null_value = true;
return 0;
}
value = args[0]->val_int();
null_value = args[0]->null_value;
return value;
}
String *Item_func_nullif::val_str(String *str) {
assert(fixed);
String *res;
if (!cmp.compare()) {
null_value = true;
return nullptr;
}
if (current_thd->is_error()) return error_str();
res = args[0]->val_str(str);
null_value = args[0]->null_value;
return res;
}
my_decimal *Item_func_nullif::val_decimal(my_decimal *decimal_value) {
assert(fixed);
my_decimal *res;
if (!cmp.compare()) {
null_value = true;
return nullptr;
}
res = args[0]->val_decimal(decimal_value);
null_value = args[0]->null_value;
return res;
}
bool Item_func_nullif::val_json(Json_wrapper *wr) {
assert(fixed);
const int cmp_result = cmp.compare();
// compare() calls val functions and may raise errors.
if (current_thd->is_error()) {
return error_json();
}
if (cmp_result == 0) {
null_value = true;
return false;
}
const bool res = args[0]->val_json(wr);
null_value = args[0]->null_value;
return res;
}
bool Item_func_nullif::is_null() {
const int result = cmp.compare();
if (current_thd->is_error()) {
null_value = true;
return true;
}
return (null_value = result == 0 ? true : args[0]->null_value);
}
/**
Find and return matching items for CASE or ELSE item if all compares
are failed or NULL if ELSE item isn't defined.
IMPLEMENTATION
In order to do correct comparisons of the CASE expression (the expression
between CASE and the first WHEN) with each WHEN expression several
comparators are used. One for each result type. CASE expression can be
evaluated up to # of different result types are used. To check whether
the CASE expression already was evaluated for a particular result type
a bit mapped variable value_added_map is used. Result types are mapped
to it according to their int values i.e. STRING_RESULT is mapped to bit
0, REAL_RESULT to bit 1, so on.
@retval
NULL Nothing found and there is no ELSE expression defined
@retval
item Found item or ELSE item if defined and all comparisons are
failed
*/
Item *Item_func_case::find_item(String *) {
uint value_added_map = 0;
if (first_expr_num == -1) {
for (uint i = 0; i < ncases; i += 2) {
// No expression between CASE and the first WHEN
if (args[i]->val_bool()) return args[i + 1];
continue;
}
} else {
/* Compare every WHEN argument with it and return the first match */
for (uint i = 0; i < ncases; i += 2) {
if (args[i]->real_item()->type() == NULL_ITEM) continue;
cmp_type = item_cmp_type(left_result_type, args[i]->result_type());
assert(cmp_type != ROW_RESULT);
assert(cmp_items[(uint)cmp_type]);
if (!(value_added_map & (1U << (uint)cmp_type))) {
cmp_items[(uint)cmp_type]->store_value(args[first_expr_num]);
if (current_thd->is_error()) {
return nullptr;
}
if ((null_value = args[first_expr_num]->null_value))
return else_expr_num != -1 ? args[else_expr_num] : nullptr;
value_added_map |= 1U << (uint)cmp_type;
}
if (cmp_items[(uint)cmp_type]->cmp(args[i]) == false) return args[i + 1];
}
}
// No, WHEN clauses all missed, return ELSE expression
return else_expr_num != -1 ? args[else_expr_num] : nullptr;
}
String *Item_func_case::val_str(String *str) {
assert(fixed);
switch (data_type()) {
case MYSQL_TYPE_DATETIME:
case MYSQL_TYPE_TIMESTAMP:
return val_string_from_datetime(str);
case MYSQL_TYPE_DATE:
return val_string_from_date(str);
case MYSQL_TYPE_TIME:
return val_string_from_time(str);
default: {
Item *item = find_item(str);
if (item != nullptr) {
String *res = item->val_str(str);
if (res != nullptr) {
res->set_charset(collation.collation);
null_value = false;
return res;
}
}
}
}
if (current_thd->is_error()) {
return error_str();
} else {
return null_return_str();
}
}
longlong Item_func_case::val_int() {
assert(fixed);
StringBuffer<MAX_FIELD_WIDTH> dummy_str(default_charset());
Item *item = find_item(&dummy_str);
if (item != nullptr) {
const longlong res = item->val_int();
null_value = item->null_value;
return res;
}
if (current_thd->is_error()) {
return error_int();
}
null_value = true;
return 0;
}
double Item_func_case::val_real() {
assert(fixed);
StringBuffer<MAX_FIELD_WIDTH> dummy_str(default_charset());
Item *item = find_item(&dummy_str);
if (item != nullptr) {
const double res = item->val_real();
null_value = item->null_value;
return res;
}
if (current_thd->is_error()) {
return error_real();
}
null_value = true;
return 0.0;
}
my_decimal *Item_func_case::val_decimal(my_decimal *decimal_value) {
assert(fixed);
StringBuffer<MAX_FIELD_WIDTH> dummy_str(default_charset());
Item *item = find_item(&dummy_str);
if (item != nullptr) {
my_decimal *res = item->val_decimal(decimal_value);
null_value = item->null_value;
return res;
}
if (current_thd->is_error()) {
return error_decimal(decimal_value);
}
null_value = true;
return nullptr;
}
bool Item_func_case::val_json(Json_wrapper *wr) {
assert(fixed);
char buff[MAX_FIELD_WIDTH];
String dummy_str(buff, sizeof(buff), default_charset());
Item *item = find_item(&dummy_str);
// Make sure that calling find_item did not result in error
if (current_thd->is_error()) return error_json();
if (item == nullptr) {
null_value = true;
return false;
}
bool has_value;
if (json_value(item, wr, &has_value)) return error_json();
assert(!current_thd->is_error() && has_value);
null_value = item->null_value;
return false;
}
bool Item_func_case::get_date(MYSQL_TIME *ltime, my_time_flags_t fuzzydate) {
assert(fixed);
char buff[MAX_FIELD_WIDTH];
String dummy_str(buff, sizeof(buff), default_charset());
Item *item = find_item(&dummy_str);
if (!item) {
null_value = is_nullable();
return true;
}
if (item->get_date(ltime, fuzzydate)) return error_date();
null_value = item->null_value;
return false;
}
bool Item_func_case::get_time(MYSQL_TIME *ltime) {
assert(fixed);
char buff[MAX_FIELD_WIDTH];
String dummy_str(buff, sizeof(buff), default_charset());
Item *item = find_item(&dummy_str);
if (!item) {
null_value = is_nullable();
return true;
}
if (item->get_time(ltime)) return error_time();
null_value = item->null_value;
return false;
}
bool Item_func_case::fix_fields(THD *thd, Item **ref) {
/*
buff should match stack usage from
Item_func_case::val_int() -> Item_func_case::find_item()
*/
uchar buff[MAX_FIELD_WIDTH * 2 + sizeof(String) * 2 + sizeof(String *) * 2 +
sizeof(double) * 2 + sizeof(longlong) * 2];
bool res = Item_func::fix_fields(thd, ref);
/*
Call check_stack_overrun after fix_fields to be sure that stack variable
is not optimized away
*/
if (check_stack_overrun(thd, STACK_MIN_SIZE, buff))
return true; // Fatal error flag is set!
return res;
}
/**
Check if (*place) and new_value points to different Items and call
THD::change_item_tree() if needed.
This function is a workaround for implementation deficiency in
Item_func_case. The problem there is that the 'args' attribute contains
Items from different expressions.
The function must not be used elsewhere and will be remove eventually.
*/
static void change_item_tree_if_needed(Item **place, Item *new_value) {
if (*place == new_value) return;
*place = new_value;
// WL#6570 remove-after-qa
assert(current_thd->stmt_arena->is_regular() ||
!current_thd->lex->is_exec_started());
}
bool Item_func_case::resolve_type(THD *thd) {
Item **agg = (Item **)thd->mem_root->Alloc(sizeof(Item *) * (ncases + 1));
if (agg == nullptr) return true;
/*
Choose types for dynamic parameters.
1) CASE value WHEN [compare_value] THEN result [WHEN [compare_value] THEN
result ...] [ELSE result] END
If ? is in value/WHEN then infer from other WHENs/value. If ? if in
THEN/ELSE then infer from other THENs/ELSE. If can't infer, use VARCHAR
for value/WHEN, but determine type from outer context for THEN/ELSE.
2) CASE WHEN [condition] THEN result [WHEN [condition] THEN result ...]
[ELSE result] END
If ? is in condition then do as for WHENs in (1).
*/
// value/WHEN
uint nagg;
for (nagg = 0; nagg < ncases / 2; nagg++) agg[nagg] = args[nagg * 2];
if (first_expr_num != -1) agg[nagg++] = args[first_expr_num];
std::swap(args, agg);
std::swap(arg_count, nagg);
if (param_type_uses_non_param(thd)) return true;
std::swap(args, agg);
std::swap(arg_count, nagg);
/*
If none of the return arguments have type, type of this operator cannot
be determined yet
*/
bool all_types_invalid = true;
for (uint i = 0; i < ncases / 2; i++)
if (args[i * 2 + 1]->data_type() != MYSQL_TYPE_INVALID)
all_types_invalid = false;
if (else_expr_num != -1 &&
args[else_expr_num]->data_type() != MYSQL_TYPE_INVALID)
all_types_invalid = false;
if (all_types_invalid) return false;
// THEN/ELSE
for (nagg = 0; nagg < ncases / 2; nagg++) agg[nagg] = args[nagg * 2 + 1];
if (else_expr_num != -1) agg[nagg++] = args[else_expr_num];
std::swap(args, agg);
std::swap(arg_count, nagg);
if (param_type_uses_non_param(thd)) return true;
std::swap(args, agg);
std::swap(arg_count, nagg);
return resolve_type_inner(thd);
}
bool Item_func_case::resolve_type_inner(THD *thd) {
/*
@todo notice that both resolve_type() and resolve_type_inner() allocate
an "agg" vector. One of the allocations is redundant and should be
eliminated. This might be done when refactoring all CASE-derived operators
to have a common base class.
*/
Item **agg = (Item **)thd->mem_root->Alloc(sizeof(Item *) * (ncases + 1));
if (agg == nullptr) return true;
// Determine nullability based on THEN and ELSE expressions:
bool nullable = else_expr_num == -1 || args[else_expr_num]->is_nullable();
for (Item **arg = args + 1; arg < args + arg_count; arg += 2)
nullable |= (*arg)->is_nullable();
set_nullable(nullable);
/*
Aggregate all THEN and ELSE expression types
and collations when string result
*/
uint nagg;
for (nagg = 0; nagg < ncases / 2; nagg++) agg[nagg] = args[nagg * 2 + 1];
if (else_expr_num != -1) agg[nagg++] = args[else_expr_num];
if (aggregate_type(func_name(), agg, nagg)) return true;
cached_result_type = Field::result_merge_type(data_type());
if (cached_result_type == STRING_RESULT) {
/*
Copy all THEN and ELSE items back to args[] array.
Some of the items might have been changed to Item_func_conv_charset.
*/
for (nagg = 0; nagg < ncases / 2; nagg++)
change_item_tree_if_needed(&args[nagg * 2 + 1], agg[nagg]);
if (else_expr_num != -1)
change_item_tree_if_needed(&args[else_expr_num], agg[nagg++]);
}
/*
Aggregate first expression and all WHEN expression types
and collations when string comparison
*/
if (first_expr_num != -1) {
agg[0] = args[first_expr_num];
left_result_type = agg[0]->result_type();
/*
As the first expression and WHEN expressions
are intermixed in args[] array THEN and ELSE items,
extract the first expression and all WHEN expressions into
a temporary array, to process them easier.
*/
for (nagg = 0; nagg < ncases / 2; nagg++) agg[nagg + 1] = args[nagg * 2];
nagg++;
const uint found_types = collect_cmp_types(agg, nagg);
if (found_types == 0) return true;
if (found_types & (1U << STRING_RESULT)) {
/*
If we'll do string comparison, we also need to aggregate
character set and collation for first/WHEN items and
install converters for some of them to cmp_collation when necessary.
This is done because cmp_item comparators cannot compare
strings in two different character sets.
Some examples when we install converters:
1. Converter installed for the first expression:
CASE latin1_item WHEN utf16_item THEN ... END
is replaced to:
CASE CONVERT(latin1_item USING utf16) WHEN utf16_item THEN ... END
2. Converter installed for the left WHEN item:
CASE utf16_item WHEN latin1_item THEN ... END
is replaced to:
CASE utf16_item WHEN CONVERT(latin1_item USING utf16) THEN ... END
*/
if (agg_arg_charsets_for_comparison(cmp_collation, agg, nagg))
return true;
/*
Now copy first expression and all WHEN expressions back to args[]
array, because some of the items might have been changed to converters
(e.g. Item_func_conv_charset, or Item_string for constants).
*/
change_item_tree_if_needed(&args[first_expr_num], agg[0]);
for (nagg = 0; nagg < ncases / 2; nagg++)
change_item_tree_if_needed(&args[nagg * 2], agg[nagg + 1]);
}
for (uint i = 0; i <= (uint)DECIMAL_RESULT; i++) {
// @todo - for time being, fill in ALL cmp_items slots
if (found_types & (1U << i) && !cmp_items[i]) {
assert((Item_result)i != ROW_RESULT);
cmp_items[i] = cmp_item::new_comparator(
thd, static_cast<Item_result>(i), args[first_expr_num],
cmp_collation.collation);
if (cmp_items[i] == nullptr) return true;
}
}
/*
Set cmp_context of all WHEN arguments. This prevents
Item_field::equal_fields_propagator() from transforming a
zerofill argument into a string constant. Such a change would
require rebuilding cmp_items.
*/
for (uint i = 0; i < ncases; i += 2)
args[i]->cmp_context =
item_cmp_type(left_result_type, args[i]->result_type());
}
return false;
}
TYPELIB *Item_func_case::get_typelib() const {
if (data_type() != MYSQL_TYPE_ENUM && data_type() != MYSQL_TYPE_SET) {
return nullptr;
}
TYPELIB *typelib = nullptr;
for (uint i = 0; i < ncases; i += 2) {
if (typelib == nullptr) {
typelib = args[i + 1]->get_typelib();
} else {
assert(args[i + 1]->get_typelib() == nullptr);
}
}
if (else_expr_num != -1 && typelib == nullptr) {
typelib = args[else_expr_num]->get_typelib();
}
assert(typelib != nullptr);
return typelib;
}
/**
@todo
Fix this so that it prints the whole CASE expression
*/
void Item_func_case::print(const THD *thd, String *str,
enum_query_type query_type) const {
str->append(STRING_WITH_LEN("(case "));
if (first_expr_num != -1) {
args[first_expr_num]->print(thd, str, query_type);
str->append(' ');
}
for (uint i = 0; i < ncases; i += 2) {
str->append(STRING_WITH_LEN("when "));
args[i]->print(thd, str, query_type);
str->append(STRING_WITH_LEN(" then "));
args[i + 1]->print(thd, str, query_type);
str->append(' ');
}
if (else_expr_num != -1) {
str->append(STRING_WITH_LEN("else "));
args[else_expr_num]->print(thd, str, query_type);
str->append(' ');
}
str->append(STRING_WITH_LEN("end)"));
}
Item_func_case::~Item_func_case() {
for (uint i = 0; i <= (uint)DECIMAL_RESULT; i++) {
if (cmp_items[i] != nullptr) {
::destroy_at(cmp_items[i]);
cmp_items[i] = nullptr;
}
}
}
/**
Coalesce - return first not NULL argument.
*/
String *Item_func_coalesce::str_op(String *str) {
assert(fixed);
null_value = false;
for (uint i = 0; i < arg_count; i++) {
String *res = args[i]->val_str(str);
if (current_thd->is_error()) return error_str();
if (res != nullptr) return res;
}
null_value = true;
return nullptr;
}
bool Item_func_coalesce::val_json(Json_wrapper *wr) {
assert(fixed);
null_value = false;
for (uint i = 0; i < arg_count; i++) {
bool has_value;
if (json_value(args[i], wr, &has_value)) return error_json();
assert(!current_thd->is_error() && has_value);
if (!args[i]->null_value) return false;
}
null_value = true;
return false;
}
longlong Item_func_coalesce::int_op() {
assert(fixed);
null_value = false;
for (uint i = 0; i < arg_count; i++) {
const longlong res = args[i]->val_int();
if (current_thd->is_error()) return error_int();
if (!args[i]->null_value) return res;
}
null_value = true;
return 0;
}
double Item_func_coalesce::real_op() {
assert(fixed);
null_value = false;
for (uint i = 0; i < arg_count; i++) {
const double res = args[i]->val_real();
if (current_thd->is_error()) return 0.0E0;
if (!args[i]->null_value) return res;
}
null_value = true;
return 0;
}
my_decimal *Item_func_coalesce::decimal_op(my_decimal *decimal_value) {
assert(fixed);
null_value = false;
for (uint i = 0; i < arg_count; i++) {
my_decimal *res = args[i]->val_decimal(decimal_value);
if (current_thd->is_error()) return error_decimal(decimal_value);
if (!args[i]->null_value) return res;
}
null_value = true;
return nullptr;
}
bool Item_func_coalesce::date_op(MYSQL_TIME *ltime, my_time_flags_t fuzzydate) {
assert(fixed);
for (uint i = 0; i < arg_count; i++) {
if (!args[i]->get_date(ltime, fuzzydate)) return (null_value = false);
}
return (null_value = true);
}
bool Item_func_coalesce::time_op(MYSQL_TIME *ltime) {
assert(fixed);
for (uint i = 0; i < arg_count; i++) {
if (!args[i]->get_time(ltime)) return (null_value = false);
}
return (null_value = true);
}
bool Item_func_coalesce::resolve_type(THD *thd) {
// If no arguments have type, type of this operator cannot be determined yet
bool all_types_invalid = true;
for (uint i = 0; i < arg_count; i++)
if (args[i]->data_type() != MYSQL_TYPE_INVALID) all_types_invalid = false;
if (all_types_invalid) return false;
return resolve_type_inner(thd);
}
bool Item_func_coalesce::resolve_type_inner(THD *thd) {
if (param_type_uses_non_param(thd)) return true;
if (aggregate_type(func_name(), args, arg_count)) return true;
hybrid_type = Field::result_merge_type(data_type());
for (uint i = 0; i < arg_count; i++) {
// A non-nullable argument guarantees a non-NULL result
if (!args[i]->is_nullable()) {
set_nullable(false);
break;
}
}
return false;
}
TYPELIB *Item_func_coalesce::get_typelib() const {
if (data_type() != MYSQL_TYPE_ENUM && data_type() != MYSQL_TYPE_SET) {
return nullptr;
}
TYPELIB *typelib = nullptr;
for (uint i = 0; i < arg_count; i++) {
if (typelib == nullptr) {
typelib = args[i]->get_typelib();
} else {
assert(args[i]->get_typelib() == nullptr);
}
}
assert(typelib != nullptr);
return typelib;
}
/****************************************************************************
Classes and function for the IN operator
****************************************************************************/
bool in_vector::fill(Item **items, uint item_count) {
m_used_size = 0;
for (uint i = 0; i < item_count; i++) {
set(m_used_size, items[i]);
if (current_thd->is_error()) return true;
/*
We don't put NULL values in array, to avoid erroneous matches in
bisection.
*/
if (!items[i]->null_value) m_used_size++; // include this cell in array.
}
assert(m_used_size <= m_size);
sort_array();
return m_used_size < item_count; // True = at least one null value found.
}
bool in_row::allocate(MEM_ROOT *mem_root, Item *lhs, uint arg_count) {
for (uint i = 0; i < arg_count; i++) {
if (base_pointers[i]->allocate_value_comparators(mem_root, tmp.get(),
lhs)) {
return true;
}
}
return false;
}
/*
Determine which of the signed longlong arguments is bigger
SYNOPSIS
cmp_longs()
a_val left argument
b_val right argument
DESCRIPTION
This function will compare two signed longlong arguments
and will return -1, 0, or 1 if left argument is smaller than,
equal to or greater than the right argument.
RETURN VALUE
-1 left argument is smaller than the right argument.
0 left argument is equal to the right argument.
1 left argument is greater than the right argument.
*/
static inline int cmp_longs(longlong a_val, longlong b_val) {
return a_val < b_val ? -1 : a_val == b_val ? 0 : 1;
}
/*
Determine which of the unsigned longlong arguments is bigger
SYNOPSIS
cmp_ulongs()
a_val left argument
b_val right argument
DESCRIPTION
This function will compare two unsigned longlong arguments
and will return -1, 0, or 1 if left argument is smaller than,
equal to or greater than the right argument.
RETURN VALUE
-1 left argument is smaller than the right argument.
0 left argument is equal to the right argument.
1 left argument is greater than the right argument.
*/
static inline int cmp_ulongs(ulonglong a_val, ulonglong b_val) {
return a_val < b_val ? -1 : a_val == b_val ? 0 : 1;
}
/*
Compare two integers in IN value list format (packed_longlong)
SYNOPSIS
cmp_longlong()
a left argument
b right argument
DESCRIPTION
This function will compare two integer arguments in the IN value list
format and will return -1, 0, or 1 if left argument is smaller than,
equal to or greater than the right argument.
It's used in sorting the IN values list and finding an element in it.
Depending on the signedness of the arguments cmp_longlong() will
compare them as either signed (using cmp_longs()) or unsigned (using
cmp_ulongs()).
RETURN VALUE
-1 left argument is smaller than the right argument.
0 left argument is equal to the right argument.
1 left argument is greater than the right argument.
*/
static int cmp_longlong(const in_longlong::packed_longlong *a,
const in_longlong::packed_longlong *b) {
if (a->unsigned_flag != b->unsigned_flag) {
/*
One of the args is unsigned and is too big to fit into the
positive signed range. Report no match.
*/
if ((a->unsigned_flag && ((ulonglong)a->val) > (ulonglong)LLONG_MAX) ||
(b->unsigned_flag && ((ulonglong)b->val) > (ulonglong)LLONG_MAX))
return a->unsigned_flag ? 1 : -1;
/*
Although the signedness differs both args can fit into the signed
positive range. Make them signed and compare as usual.
*/
return cmp_longs(a->val, b->val);
}
if (a->unsigned_flag)
return cmp_ulongs((ulonglong)a->val, (ulonglong)b->val);
else
return cmp_longs(a->val, b->val);
}
class Cmp_longlong {
public:
bool operator()(const in_longlong::packed_longlong &a,
const in_longlong::packed_longlong &b) {
return cmp_longlong(&a, &b) < 0;
}
};
void in_longlong::sort_array() {
std::sort(base.begin(), base.begin() + m_used_size, Cmp_longlong());
}
bool in_longlong::find_item(Item *item) {
if (m_used_size == 0) return false;
packed_longlong result;
val_item(item, &result);
if (item->null_value) return false;
return std::binary_search(base.begin(), base.begin() + m_used_size, result,
Cmp_longlong());
}
bool in_longlong::compare_elems(uint pos1, uint pos2) const {
return cmp_longlong(&base[pos1], &base[pos2]) != 0;
}
class Cmp_row {
public:
bool operator()(const cmp_item_row *a, const cmp_item_row *b) {
return a->compare(b) < 0;
}
};
void in_row::sort_array() {
std::sort(base_pointers.begin(), base_pointers.begin() + m_used_size,
Cmp_row());
}
bool in_row::find_item(Item *item) {
if (m_used_size == 0) return false;
tmp->store_value(item);
if (item->null_value) return false;
return std::binary_search(base_pointers.begin(),
base_pointers.begin() + m_used_size, tmp.get(),
Cmp_row());
}
bool in_row::compare_elems(uint pos1, uint pos2) const {
return base_pointers[pos1]->compare(base_pointers[pos2]) != 0;
}
in_string::in_string(MEM_ROOT *mem_root, uint elements, const CHARSET_INFO *cs)
: in_vector(elements),
tmp(buff, sizeof(buff), &my_charset_bin),
base_objects(mem_root, elements),
base_pointers(mem_root, elements),
collation(cs) {
for (uint ix = 0; ix < elements; ++ix) {
base_pointers[ix] = &base_objects[ix];
}
}
void in_string::cleanup() {
// Clear reference pointers and free any memory allocated for holding data.
for (uint i = 0; i < m_used_size; i++) {
String *str = base_pointers[i];
str->set(static_cast<const char *>(nullptr), 0, str->charset());
}
}
void in_string::set(uint pos, Item *item) {
String *str = base_pointers[pos];
String *res = eval_string_arg(collation, item, str);
if (res == nullptr || res == str) return;
if (res->uses_buffer_owned_by(str)) res->copy();
if (item->type() == Item::FUNC_ITEM)
str->copy(*res);
else
*str = *res;
}
static int srtcmp_in(const CHARSET_INFO *cs, const String *x, const String *y) {
return cs->coll->strnncollsp(
cs, pointer_cast<const uchar *>(x->ptr()), x->length(),
pointer_cast<const uchar *>(y->ptr()), y->length());
}
namespace {
class Cmp_string {
public:
explicit Cmp_string(const CHARSET_INFO *cs) : collation(cs) {}
bool operator()(const String *a, const String *b) const {
return srtcmp_in(collation, a, b) < 0;
}
private:
const CHARSET_INFO *collation;
};
} // namespace
// Sort string pointers, not string objects.
void in_string::sort_array() {
std::sort(base_pointers.begin(), base_pointers.begin() + m_used_size,
Cmp_string(collation));
}
bool in_string::find_item(Item *item) {
if (m_used_size == 0) return false;
const String *str = eval_string_arg(collation, item, &tmp);
if (str == nullptr) return false;
if (current_thd->is_error()) return false;
return std::binary_search(base_pointers.begin(),
base_pointers.begin() + m_used_size, str,
Cmp_string(collation));
}
bool in_string::compare_elems(uint pos1, uint pos2) const {
return srtcmp_in(collation, base_pointers[pos1], base_pointers[pos2]) != 0;
}
in_row::in_row(MEM_ROOT *mem_root, uint elements, cmp_item_row *cmp)
: in_vector(elements),
tmp(cmp),
base_objects(mem_root, elements),
base_pointers(mem_root, elements) {
for (uint ix = 0; ix < elements; ++ix) {
base_pointers[ix] = &base_objects[ix];
}
}
void in_row::set(uint pos, Item *item) {
DBUG_TRACE;
DBUG_PRINT("enter", ("pos: %u item: %p", pos, item));
base_pointers[pos]->store_value_by_template(tmp.get(), item);
}
void in_longlong::val_item(Item *item, packed_longlong *result) {
result->val = item->val_int();
result->unsigned_flag = item->unsigned_flag;
}
void in_time_as_longlong::val_item(Item *item, packed_longlong *result) {
result->val = item->val_time_temporal();
result->unsigned_flag = item->unsigned_flag;
}
void in_datetime_as_longlong::val_item(Item *item, packed_longlong *result) {
result->val = item->val_date_temporal();
result->unsigned_flag = item->unsigned_flag;
}
void in_datetime::set(uint pos, Item *item) {
Item **p = &item;
bool is_null;
struct packed_longlong *buff = &base[pos];
buff->val = get_datetime_value(current_thd, &p, nullptr, warn_item, &is_null);
buff->unsigned_flag = true;
}
void in_datetime::val_item(Item *item, packed_longlong *result) {
bool is_null;
Item **p = &item;
result->val =
get_datetime_value(current_thd, &p, nullptr, warn_item, &is_null);
result->unsigned_flag = true;
}
void in_double::set(uint pos, Item *item) { base[pos] = item->val_real(); }
void in_double::sort_array() {
std::sort(base.begin(), base.begin() + m_used_size);
}
bool in_double::find_item(Item *item) {
if (m_used_size == 0) return false;
const double dbl = item->val_real();
if (item->null_value) return false;
return std::binary_search(base.begin(), base.begin() + m_used_size, dbl);
}
bool in_double::compare_elems(uint pos1, uint pos2) const {
return base[pos1] != base[pos2];
}
void in_decimal::set(uint pos, Item *item) {
/* as far as 'item' is constant, we can store reference on my_decimal */
my_decimal *dec = &base[pos];
my_decimal *res = item->val_decimal(dec);
/* if item->val_decimal() is evaluated to NULL then res == 0 */
if (!item->null_value && res != dec) my_decimal2decimal(res, dec);
}
void in_decimal::sort_array() {
std::sort(base.begin(), base.begin() + m_used_size);
}
bool in_decimal::find_item(Item *item) {
if (m_used_size == 0) return false;
my_decimal val;
const my_decimal *dec = item->val_decimal(&val);
if (item->null_value) return false;
return std::binary_search(base.begin(), base.begin() + m_used_size, *dec);
}
bool in_decimal::compare_elems(uint pos1, uint pos2) const {
return base[pos1] != base[pos2];
}
bool cmp_item::allocate_value_comparators(MEM_ROOT *, cmp_item *, Item *) {
return false;
}
cmp_item *cmp_item::new_comparator(THD *thd, Item_result result_type,
Item *item, const CHARSET_INFO *cs) {
switch (result_type) {
case STRING_RESULT:
/*
Temporal types shouldn't be compared as strings. Since date/time formats
may be different, e.g. '20000102' == '2000-01-02'."
*/
if (item->is_temporal())
return new (*THR_MALLOC) cmp_item_datetime(item);
else
return new (*THR_MALLOC) cmp_item_string(cs);
case INT_RESULT:
return new (*THR_MALLOC) cmp_item_int;
case REAL_RESULT:
return new (*THR_MALLOC) cmp_item_real;
case ROW_RESULT:
return new (*THR_MALLOC) cmp_item_row(thd, item);
case DECIMAL_RESULT:
return new (*THR_MALLOC) cmp_item_decimal;
default:
assert(false);
break;
}
return nullptr; // to satisfy compiler :)
}
cmp_item *cmp_item_string::make_same() {
return new (*THR_MALLOC) cmp_item_string(cmp_charset);
}
int cmp_item_string::cmp(Item *arg) {
if (m_null_value) return UNKNOWN;
StringBuffer<STRING_BUFFER_USUAL_SIZE> tmp(cmp_charset);
String *res = eval_string_arg(cmp_charset, arg, &tmp);
if (res == nullptr) return UNKNOWN;
return sortcmp(value_res, res, cmp_charset) != 0;
}
cmp_item *cmp_item_int::make_same() { return new (*THR_MALLOC) cmp_item_int(); }
cmp_item *cmp_item_real::make_same() {
return new (*THR_MALLOC) cmp_item_real();
}
cmp_item *cmp_item_row::make_same() { return new (*THR_MALLOC) cmp_item_row(); }
cmp_item_json::cmp_item_json(unique_ptr_destroy_only<Json_wrapper> wrapper,
unique_ptr_destroy_only<Json_scalar_holder> holder)
: m_value(std::move(wrapper)), m_holder(std::move(holder)) {}
cmp_item_json::~cmp_item_json() = default;
/// Create a cmp_item_json object on a MEM_ROOT.
static cmp_item_json *make_cmp_item_json(MEM_ROOT *mem_root) {
auto wrapper = make_unique_destroy_only<Json_wrapper>(mem_root);
if (wrapper == nullptr) return nullptr;
auto holder = make_unique_destroy_only<Json_scalar_holder>(mem_root);
if (holder == nullptr) return nullptr;
return new (mem_root) cmp_item_json(std::move(wrapper), std::move(holder));
}
cmp_item *cmp_item_json::make_same() { return make_cmp_item_json(*THR_MALLOC); }
int cmp_item_json::compare(const cmp_item *ci) const {
const cmp_item_json *l_cmp = down_cast<const cmp_item_json *>(ci);
return m_value->compare(*l_cmp->m_value);
}
void cmp_item_json::store_value(Item *item) {
bool err = false;
if (item->data_type() == MYSQL_TYPE_JSON)
err = item->val_json(m_value.get());
else {
String tmp;
err = get_json_atom_wrapper(&item, 0, "IN", &m_str_value, &tmp,
m_value.get(), m_holder.get(), true);
}
set_null_value(err || item->null_value);
}
int cmp_item_json::cmp(Item *arg) {
Json_scalar_holder holder;
Json_wrapper wr;
if (m_null_value) return UNKNOWN;
if (arg->data_type() == MYSQL_TYPE_JSON) {
if (arg->val_json(&wr) || arg->null_value) return UNKNOWN;
} else {
String tmp, str;
if (get_json_atom_wrapper(&arg, 0, "IN", &str, &tmp, &wr, &holder, true) ||
arg->null_value)
return UNKNOWN; /* purecov: inspected */
}
return m_value->compare(wr) ? 1 : 0;
}
cmp_item_row::~cmp_item_row() {
DBUG_TRACE;
DBUG_PRINT("enter", ("this: %p", this));
if (comparators) {
for (uint i = 0; i < n; i++) {
if (comparators[i] != nullptr) ::destroy_at(comparators[i]);
}
}
}
bool cmp_item_row::allocate_template_comparators(THD *thd, Item *item) {
assert(n == item->cols());
n = item->cols();
assert(comparators == nullptr);
comparators = thd->mem_root->ArrayAlloc<cmp_item *>(n);
if (comparators == nullptr) return true;
for (uint i = 0; i < n; i++) {
assert(comparators[i] == nullptr);
Item *item_i = item->element_index(i);
comparators[i] = cmp_item::new_comparator(
thd, item_i->result_type(), item_i, item_i->collation.collation);
if (comparators[i] == nullptr) return true; // Allocation failed
}
return false;
}
void cmp_item_row::store_value(Item *item) {
DBUG_TRACE;
assert(comparators != nullptr);
item->null_value = false;
item->bring_value();
if (item->null_value) {
set_null_value(/*nv=*/true);
} else {
item->null_value = false;
for (uint i = 0; i < n; i++) {
comparators[i]->store_value(item->element_index(i));
item->null_value |= item->element_index(i)->null_value;
}
}
}
bool cmp_item_row::allocate_value_comparators(MEM_ROOT *mem_root,
cmp_item *tmpl, Item *item) {
cmp_item_row *row_template = down_cast<cmp_item_row *>(tmpl);
assert(row_template->n == item->cols());
n = row_template->n;
assert(comparators == nullptr);
comparators = (cmp_item **)mem_root->Alloc(sizeof(cmp_item *) * n);
if (comparators == nullptr) return true;
for (uint i = 0; i < n; i++) {
comparators[i] = row_template->comparators[i]->make_same();
if (comparators[i] == nullptr) return true;
if (comparators[i]->allocate_value_comparators(
mem_root, row_template->comparators[i], item->element_index(i))) {
return true;
}
}
return false;
}
void cmp_item_row::store_value_by_template(cmp_item *t, Item *item) {
cmp_item_row *tmpl = (cmp_item_row *)t;
item->null_value = false;
item->bring_value();
if (item->null_value) {
set_null_value(/*nv=*/true);
} else {
item->null_value = false;
for (uint i = 0; i < n; i++) {
comparators[i]->store_value_by_template(tmpl->comparators[i],
item->element_index(i));
item->null_value |= item->element_index(i)->null_value;
}
}
}
int cmp_item_row::cmp(Item *arg) {
arg->null_value = false;
if (arg->cols() != n) {
my_error(ER_OPERAND_COLUMNS, MYF(0), n);
return 1;
}
bool was_null = false;
arg->bring_value();
for (uint i = 0; i < n; i++) {
const int rc = comparators[i]->cmp(arg->element_index(i));
switch (rc) {
case UNKNOWN:
was_null = true;
break;
case true:
return true;
case false:
break; // elements #i are equal
}
arg->null_value |= arg->element_index(i)->null_value;
}
return was_null ? UNKNOWN : false;
}
int cmp_item_row::compare(const cmp_item *c) const {
const cmp_item_row *l_cmp = down_cast<const cmp_item_row *>(c);
for (uint i = 0; i < n; i++) {
int res;
if ((res = comparators[i]->compare(l_cmp->comparators[i]))) return res;
}
return 0;
}
void cmp_item_decimal::store_value(Item *item) {
my_decimal *val = item->val_decimal(&value);
/* val may be zero if item is nnull */
if (val && val != &value) my_decimal2decimal(val, &value);
set_null_value(item->null_value);
}
int cmp_item_decimal::cmp(Item *arg) {
my_decimal tmp_buf, *tmp = arg->val_decimal(&tmp_buf);
return (m_null_value || arg->null_value) ? UNKNOWN
: (my_decimal_cmp(&value, tmp) != 0);
}
int cmp_item_decimal::compare(const cmp_item *arg) const {
const cmp_item_decimal *l_cmp = down_cast<const cmp_item_decimal *>(arg);
return my_decimal_cmp(&value, &l_cmp->value);
}
cmp_item *cmp_item_decimal::make_same() {
return new (*THR_MALLOC) cmp_item_decimal();
}
cmp_item_datetime::cmp_item_datetime(const Item *warn_item_arg)
: warn_item(warn_item_arg),
has_date(warn_item_arg->is_temporal_with_date()) {}
void cmp_item_datetime::store_value(Item *item) {
bool is_null;
Item **p = &item;
if (has_date)
value = get_datetime_value(current_thd, &p, nullptr, warn_item, &is_null);
else
value = get_time_value(current_thd, &p, nullptr, nullptr, &is_null);
set_null_value(item->null_value);
}
int cmp_item_datetime::cmp(Item *item) {
bool is_null;
longlong value2 = 0;
Item **p = &item;
if (has_date)
value2 = get_datetime_value(current_thd, &p, nullptr, warn_item, &is_null);
else
value2 = get_time_value(current_thd, &p, nullptr, nullptr, &is_null);
const bool rc = (value != value2);
return (m_null_value || item->null_value) ? UNKNOWN : rc;
}
int cmp_item_datetime::compare(const cmp_item *ci) const {
const cmp_item_datetime *l_cmp = down_cast<const cmp_item_datetime *>(ci);
return (value < l_cmp->value) ? -1 : ((value == l_cmp->value) ? 0 : 1);
}
cmp_item *cmp_item_datetime::make_same() {
return new (*THR_MALLOC) cmp_item_datetime(warn_item);
}
float Item_func_in::get_single_col_filtering_effect(
Item_ident *fieldref, table_map filter_for_table,
const MY_BITMAP *fields_to_ignore, double rows_in_table) {
/*
Does not contribute to filtering effect if
1) This field belongs to another table.
2) Filter effect for this field has already been taken into
account. 'fieldref' may be a field or a reference to a field
(through a view, to an outer table etc)
*/
if ((fieldref->used_tables() != filter_for_table) || // 1)
bitmap_is_set(fields_to_ignore,
static_cast<Item_field *>(fieldref->real_item())
->field->field_index())) // 2)
return COND_FILTER_ALLPASS;
const Item_field *fld = (Item_field *)fieldref->real_item();
return fld->get_cond_filter_default_probability(rows_in_table,
COND_FILTER_EQUALITY);
}
float Item_func_in::get_filtering_effect(THD *thd, table_map filter_for_table,
table_map read_tables,
const MY_BITMAP *fields_to_ignore,
double rows_in_table) {
assert((read_tables & filter_for_table) == 0);
/*
To contribute to filtering effect, the condition must refer to
exactly one unread table: the table filtering is currently
calculated for.
Dependent subqueries are not considered available values and no
filtering should be calculated for this item if the IN list
contains one. dep_subq_in_list is 'true' if the IN list contains a
dependent subquery.
*/
if ((used_tables() & ~read_tables) != filter_for_table || dep_subq_in_list)
return COND_FILTER_ALLPASS;
/*
No matter how many row values are input the filtering effect
shall not be higher than in_max_filter (currently 0.5).
*/
const float in_max_filter = 0.5f;
float filter = COND_FILTER_ALLPASS;
if (args[0]->type() == Item::ROW_ITEM) {
/*
This is a row value IN predicate:
"WHERE (col1, col2, ...) IN ((1,2,..), ...)"
which can be rewritten to:
"WHERE (col1=1 AND col2=2...) OR (col1=.. AND col2=...) OR ..."
The filtering effect is:
filter= #row_values * filter(<single_row_value>)
where filter(<single_row_value>) = filter(col1) * filter(col2) * ...
In other words, we ignore the fact that there could be identical
row values since writing "WHERE (a,b) IN ((1,1), (1,1), ...)" is
not expected input from a user.
*/
Item_row *lhs_row = static_cast<Item_row *>(args[0]);
// For all items in the left row
float single_rowval_filter = COND_FILTER_ALLPASS;
for (uint i = 0; i < lhs_row->cols(); i++) {
/*
May contribute to condition filtering only if
lhs_row->element_index(i) is a field or a reference to a field
(through a view, to an outer table etc)
*/
if (lhs_row->element_index(i)->real_item()->type() == Item::FIELD_ITEM) {
Item_ident *fieldref =
static_cast<Item_ident *>(lhs_row->element_index(i));
const float tmp_filt = get_single_col_filtering_effect(
fieldref, filter_for_table, fields_to_ignore, rows_in_table);
single_rowval_filter *= tmp_filt;
}
}
/*
If single_rowval_filter == COND_FILTER_ALLPASS, the filtering
effect of this field should be ignored. If not, selectivity
should not be higher than 'in_max_filter' even if there are a
lot of values on the right hand side
arg_count includes the left hand side item
*/
if (single_rowval_filter != COND_FILTER_ALLPASS)
filter = min((arg_count - 1) * single_rowval_filter, in_max_filter);
} else if (args[0]->real_item()->type() == Item::FIELD_ITEM) {
/*
This is a single-column IN predicate:
"WHERE col IN (1, 2, ...)"
which can be rewritten to:
"WHERE col=1 OR col1=2 OR ..."
The filtering effect is: #values_right_hand_side * selectivity(=)
As for row values, it is assumed that no values on the right
hand side are identical.
*/
assert(args[0]->type() == FIELD_ITEM || args[0]->type() == REF_ITEM);
if (args[0]->type() == FIELD_ITEM) {
const Item_field *item_field = down_cast<const Item_field *>(args[0]);
const histograms::enum_operator op =
(negated ? histograms::enum_operator::NOT_IN_LIST
: histograms::enum_operator::IN_LIST);
const double selectivity =
get_histogram_selectivity(thd, *item_field->field, op, *this);
if (selectivity != kUndefinedSelectivity) {
return selectivity;
}
}
Item_ident *fieldref = static_cast<Item_ident *>(args[0]);
const float tmp_filt = get_single_col_filtering_effect(
fieldref, filter_for_table, fields_to_ignore, rows_in_table);
/*
If tmp_filt == COND_FILTER_ALLPASS, the filtering effect of this
field should be ignored. If not, selectivity should not be
higher than 'in_max_filter' even if there are a lot of values on
the right hand side
arg_count includes the left hand side item
*/
if (tmp_filt != COND_FILTER_ALLPASS)
filter = min((arg_count - 1) * tmp_filt, in_max_filter);
}
if (negated && filter != COND_FILTER_ALLPASS) filter = 1.0f - filter;
assert(filter >= 0.0f && filter <= 1.0f);
return filter;
}
bool Item_func_in::list_contains_null() {
Item **arg, **arg_end;
for (arg = args + 1, arg_end = args + arg_count; arg != arg_end; arg++) {
if ((*arg)->null_inside()) return true;
}
return false;
}
/**
Perform context analysis of an IN item tree.
This function performs context analysis (name resolution) and calculates
various attributes of the item tree with Item_func_in as its root.
The function saves in ref the pointer to the item or to a newly created
item that is considered as a replacement for the original one.
@param thd reference to the global context of the query thread
@param ref pointer to Item* variable where pointer to resulting "fixed"
item is to be assigned
@note
Let T0(e)/T1(e) be the value of not_null_tables(e) when e is used on
a predicate/function level. Then it's easy to show that:
@verbatim
T0(e IN(e1,...,en)) = union(T1(e),intersection(T1(ei)))
T1(e IN(e1,...,en)) = union(T1(e),intersection(T1(ei)))
T0(e NOT IN(e1,...,en)) = union(T1(e),union(T1(ei)))
T1(e NOT IN(e1,...,en)) = union(T1(e),intersection(T1(ei)))
@endverbatim
@retval
0 ok
@retval
1 got error
*/
bool Item_func_in::fix_fields(THD *thd, Item **ref) {
if (Item_func_opt_neg::fix_fields(thd, ref)) return true;
update_not_null_tables();
return false;
}
void Item_func_in::fix_after_pullout(Query_block *parent_query_block,
Query_block *removed_query_block) {
Item_func_opt_neg::fix_after_pullout(parent_query_block, removed_query_block);
update_not_null_tables();
}
bool Item_func_in::resolve_type(THD *thd) {
if (Item_func_opt_neg::resolve_type(thd)) return true;
/* true <=> arguments values will be compared as DATETIMEs. */
bool compare_as_datetime = false;
Item *date_arg = nullptr;
bool compare_as_json = (args[0]->data_type() == MYSQL_TYPE_JSON);
left_result_type = args[0]->result_type();
Item_result cmp_type = STRING_RESULT;
const uint found_types = collect_cmp_types(args, arg_count, true);
if (found_types == 0) return true;
m_values_are_const = true;
m_need_populate = false;
Item **arg_end = args + arg_count;
for (Item **arg = args + 1; arg != arg_end; arg++) {
compare_as_json |= (arg[0]->data_type() == MYSQL_TYPE_JSON);
if (!(*arg)->const_for_execution()) {
m_values_are_const = false;
// @todo - rewrite as has_subquery() ???
if ((*arg)->real_item()->type() == Item::SUBQUERY_ITEM)
dep_subq_in_list = true;
break;
} else {
// Some items may change per execution - trigger repopulation
if (!(*arg)->const_item()) {
m_need_populate = true;
}
}
}
if (compare_as_json) {
for (Item **arg = args + 1; arg != arg_end; arg++) {
(*arg)->mark_json_as_scalar();
}
}
uint type_cnt = 0;
for (uint i = 0; i <= (uint)DECIMAL_RESULT; i++) {
if (found_types & (1U << i)) {
(type_cnt)++;
cmp_type = (Item_result)i;
}
}
/*
Set cmp_context of all arguments. This prevents
Item_field::equal_fields_propagator() from transforming a zerofill integer
argument into a string constant. Such a change would require rebuilding
cmp_items.
*/
for (Item **arg = args + 1; arg != arg_end; arg++) {
(*arg)->cmp_context =
item_cmp_type(left_result_type, arg[0]->result_type());
}
max_length = 1;
if (m_const_array != nullptr) {
/*
A previously allocated const array exists; so we are now allocating in the
execution MEM_ROOT a new array only for this execution; delete the old
one now; take note to delete the new one in cleanup().
@see substitute_gc_expression().
*/
first_resolve_call = false;
m_need_populate = true;
cleanup_arrays();
} else {
for (uint i = 0; i <= (uint)DECIMAL_RESULT + 1; i++) {
if (cmp_items[i]) { // Same thing
first_resolve_call = false;
m_need_populate = true;
cleanup_arrays();
break;
}
}
}
/*
First conditions for bisection to be possible:
1. All types are similar, and
2. All expressions in <in value list> are const (for execution)
3. No JSON is compared (in such case universal JSON comparator is used)
*/
bool bisection_possible = type_cnt == 1 && // 1
m_values_are_const && // 2
!compare_as_json; // 3
if (bisection_possible) {
/*
In the presence of NULLs, the correct result of evaluating this item
must be UNKNOWN or FALSE. To achieve that:
- If type is scalar, we can use bisection and the "have_null" boolean.
- If type is ROW, we will need to scan all of <in value list> when
searching, so bisection is impossible. Unless:
3. UNKNOWN and FALSE are equivalent results
4. Neither left expression nor <in value list> contain any NULL value
*/
if (cmp_type == ROW_RESULT &&
!((ignore_unknown() && !negated) || // 3
(!list_contains_null() && !args[0]->is_nullable()))) // 4
bisection_possible = false;
}
if (type_cnt == 1 && !compare_as_json) {
if (cmp_type == STRING_RESULT &&
agg_arg_charsets_for_comparison(cmp_collation, args, arg_count))
return true;
/*
When comparing rows create the row comparator object beforehand to ease
the DATETIME comparison detection procedure.
*/
if (cmp_type == ROW_RESULT) {
assert(first_resolve_call);
cmp_item_row *cmp = new (thd->mem_root) cmp_item_row(thd, args[0]);
if (cmp == nullptr) return true;
if (bisection_possible) {
m_const_array =
new (thd->mem_root) in_row(thd->mem_root, arg_count - 1, cmp);
if (m_const_array == nullptr) return true;
if (down_cast<in_row *>(m_const_array)
->allocate(thd->mem_root, args[0], arg_count - 1)) {
return true;
}
} else {
cmp_items[ROW_RESULT] = cmp;
}
}
/* All DATE/DATETIME fields/functions has the STRING result type. */
if (cmp_type == STRING_RESULT || cmp_type == ROW_RESULT) {
bool datetime_found = false;
const uint num_cols = args[0]->cols();
// Proper JSON comparison isn't yet supported if JSON is within a ROW
bool json_row_warning_printed = (num_cols == 1);
for (uint col = 0; col < num_cols; col++) {
/*
Check that all items to be compared has the STRING result type and at
least one of them is a DATE/DATETIME item.
*/
for (Item **arg = args; arg != arg_end; arg++) {
Item *itm =
((cmp_type == STRING_RESULT) ? arg[0]
: arg[0]->element_index(col));
if (itm->data_type() == MYSQL_TYPE_JSON &&
!json_row_warning_printed) {
json_row_warning_printed = true;
push_warning_printf(
current_thd, Sql_condition::SL_WARNING, ER_NOT_SUPPORTED_YET,
ER_THD(current_thd, ER_NOT_SUPPORTED_YET),
"comparison of JSON within a ROW in the IN operator");
}
if (itm->result_type() != STRING_RESULT) {
// If the warning wasn't printed yet, we need to continue scanning
// through args to check whether one of them is JSON
if (json_row_warning_printed)
break;
else
continue;
} else if (itm->is_temporal_with_date()) {
datetime_found = true;
/*
Internally all DATE/DATETIME values are converted to the DATETIME
type. So try to find a DATETIME item to issue correct warnings.
*/
if (!date_arg)
date_arg = itm;
else if (itm->data_type() == MYSQL_TYPE_DATETIME) {
date_arg = itm;
/* All arguments are already checked to have the STRING result. */
if (cmp_type == STRING_RESULT) break;
}
}
}
}
compare_as_datetime = (datetime_found && cmp_type != ROW_RESULT);
}
}
if (bisection_possible) {
if (compare_as_datetime) {
m_const_array = new (thd->mem_root)
in_datetime(thd->mem_root, date_arg, arg_count - 1);
if (m_const_array == nullptr) return true;
} else {
/*
IN must compare INT columns and constants as int values (the same
way as equality does).
So we must check here if the column on the left and all the constant
values on the right can be compared as integers and adjust the
comparison type accordingly.
*/
bool datetime_as_longlong = false;
if (args[0]->real_item()->type() == FIELD_ITEM &&
thd->lex->sql_command != SQLCOM_CREATE_VIEW &&
thd->lex->sql_command != SQLCOM_SHOW_CREATE &&
cmp_type != INT_RESULT) {
Item_field *field_item = (Item_field *)(args[0]->real_item());
if (field_item->field->can_be_compared_as_longlong()) {
bool all_converted = true;
for (Item **arg = args + 1; arg != arg_end; arg++) {
bool converted;
if (convert_constant_item(thd, field_item, &arg[0], &converted))
return true;
all_converted &= converted;
}
if (all_converted) {
cmp_type = INT_RESULT;
datetime_as_longlong = field_item->is_temporal() &&
field_item->data_type() != MYSQL_TYPE_YEAR;
}
}
}
switch (cmp_type) {
case STRING_RESULT:
m_const_array = new (thd->mem_root)
in_string(thd->mem_root, arg_count - 1, cmp_collation.collation);
break;
case INT_RESULT:
m_const_array =
datetime_as_longlong
? args[0]->data_type() == MYSQL_TYPE_TIME
? static_cast<in_vector *>(
new (thd->mem_root) in_time_as_longlong(
thd->mem_root, arg_count - 1))
: static_cast<in_vector *>(
new (thd->mem_root) in_datetime_as_longlong(
thd->mem_root, arg_count - 1))
: static_cast<in_vector *>(new (thd->mem_root) in_longlong(
thd->mem_root, arg_count - 1));
break;
case REAL_RESULT:
m_const_array =
new (thd->mem_root) in_double(thd->mem_root, arg_count - 1);
break;
case ROW_RESULT:
/*
The row comparator was created at the beginning.
*/
break;
case DECIMAL_RESULT:
m_const_array =
new (thd->mem_root) in_decimal(thd->mem_root, arg_count - 1);
break;
default:
assert(0);
}
if (m_const_array == nullptr) return true;
}
/*
convert_constant_item() or one of its descendants might set an error
without correct propagation of return value. Bail out if error.
(Should be an assert).
*/
if (thd->is_error()) return true;
} else {
if (compare_as_json) {
// Use JSON comparator for all comparison types
for (uint i = 0; i <= (uint)DECIMAL_RESULT; i++) {
if (/* (found_types & (1U << i) && */ !cmp_items[i]) {
cmp_items[i] = make_cmp_item_json(thd->mem_root);
if (cmp_items[i] == nullptr) return true; /* purecov: inspected */
}
}
} else if (compare_as_datetime) {
if (!(cmp_items[STRING_RESULT] =
new (thd->mem_root) cmp_item_datetime(date_arg)))
return true;
} else {
for (uint i = 0; i <= (uint)DECIMAL_RESULT; i++) {
if (found_types & (1U << i) && !cmp_items[i]) {
if ((Item_result)i == STRING_RESULT &&
agg_arg_charsets_for_comparison(cmp_collation, args, arg_count))
return true;
if (!cmp_items[i] &&
!(cmp_items[i] = cmp_item::new_comparator(
thd, (Item_result)i, args[0], cmp_collation.collation)))
return true;
}
}
}
}
if (thd->lex->is_view_context_analysis()) return false;
if (m_const_array != nullptr && m_values_are_const && !m_need_populate) {
have_null = m_const_array->fill(args + 1, arg_count - 1);
m_populated = true;
}
Opt_trace_object(&thd->opt_trace)
.add("IN_uses_bisection", bisection_possible);
return false;
}
void Item_func_in::update_used_tables() {
Item_func::update_used_tables();
update_not_null_tables();
}
void Item_func_in::print(const THD *thd, String *str,
enum_query_type query_type) const {
str->append('(');
args[0]->print(thd, str, query_type);
if (negated) str->append(STRING_WITH_LEN(" not"));
str->append(STRING_WITH_LEN(" in ("));
print_args(thd, str, 1, query_type);
str->append(STRING_WITH_LEN("))"));
}
/*
Evaluate the function and return its value.
SYNOPSIS
val_int()
DESCRIPTION
Evaluate the function and return its value.
IMPLEMENTATION
If the array object is defined then the value of the function is
calculated by means of this array.
Otherwise several cmp_item objects are used in order to do correct
comparison of left expression and an expression from the values list.
One cmp_item object correspond to one used comparison type. Left
expression can be evaluated up to number of different used comparison
types. A bit mapped variable value_added_map is used to check whether
the left expression already was evaluated for a particular result type.
Result types are mapped to it according to their integer values i.e.
STRING_RESULT is mapped to bit 0, REAL_RESULT to bit 1, so on.
RETURN
Value of the function
*/
longlong Item_func_in::val_int() {
cmp_item *in_item;
assert(fixed);
uint value_added_map = 0;
if (m_const_array != nullptr) {
if (!m_populated) {
have_null = m_const_array->fill(args + 1, arg_count - 1);
if (current_thd->is_error()) return error_int();
m_populated = true;
}
const bool tmp = m_const_array->find_item(args[0]);
/*
NULL on left -> UNKNOWN.
Found no match, and NULL on right -> UNKNOWN.
NULL on right can never give a match, as it is not stored in
array.
See also the 'bisection_possible' variable in resolve_type().
*/
null_value = args[0]->null_value || (!tmp && have_null);
return (longlong)(!null_value && tmp != negated);
}
if ((null_value = args[0]->real_item()->type() == NULL_ITEM)) return 0;
have_null = false;
for (uint i = 1; i < arg_count; i++) {
if (args[i]->real_item()->type() == NULL_ITEM) {
have_null = true;
continue;
}
const Item_result cmp_type =
item_cmp_type(left_result_type, args[i]->result_type());
in_item = cmp_items[(uint)cmp_type];
assert(in_item);
if (!(value_added_map & (1U << (uint)cmp_type))) {
in_item->store_value(args[0]);
value_added_map |= 1U << (uint)cmp_type;
if (current_thd->is_error()) return error_int();
}
const int rc = in_item->cmp(args[i]);
if (rc == false) return (longlong)(!negated);
have_null |= (rc == UNKNOWN);
if (current_thd->is_error()) return error_int();
}
null_value = have_null;
return (longlong)(!null_value && negated);
}
bool Item_func_in::populate_bisection(THD *) {
assert(!m_populated);
have_null = m_const_array->fill(args + 1, arg_count - 1);
m_populated = true;
return false;
}
void Item_func_in::cleanup_arrays() {
m_populated = false;
if (m_const_array != nullptr) ::destroy_at(m_const_array);
m_const_array = nullptr;
for (uint i = 0; i <= (uint)DECIMAL_RESULT + 1; i++) {
if (cmp_items[i] != nullptr) {
::destroy_at(cmp_items[i]);
cmp_items[i] = nullptr;
}
}
}
void Item_func_in::cleanup() {
DBUG_TRACE;
Item_int_func::cleanup();
// Trigger re-population in next execution (if bisection is used)
if (m_need_populate) {
if (m_const_array != nullptr) m_const_array->cleanup();
m_populated = false;
}
if (!first_resolve_call) {
/*
2nd and next calls to resolve_type() allocated in execution MEM_ROOT; at
the end of this execution we must delete the objects, as their storage
will soon be freed.
On the opposite, the objects allocated by the first call are in the
persistent MEM_ROOT and, if they have not been deleted and replaced by
some 2nd call, they are to be deleted by the destructor, no earlier -
they may serve for multiple executions.
*/
cleanup_arrays();
}
}
Item_func_in::~Item_func_in() { cleanup_arrays(); }
Item_cond::Item_cond(THD *thd, Item_cond *item)
: Item_bool_func(thd, item), abort_on_null(item->abort_on_null) {
/*
item->list will be copied by copy_andor_arguments() call
*/
}
/**
Ensure that all expressions involved in conditions are boolean functions.
Specifically, change <non-bool-expr> to (0 <> <non-bool-expr>)
@param pc Parse context, including memroot for Item construction
@param item Any expression, if not a boolean expression, convert it
@returns = NULL Error
<> NULL A boolean expression, possibly constructed as described above
@note Due to the special conditions of a MATCH expression (it is both a
function returning a floating point value and it may be used
standalone in the WHERE clause), it is wrapped inside a special
Item_func_match_predicate, instead of forming a non-equality.
*/
Item *make_condition(Parse_context *pc, Item *item) {
assert(!item->is_bool_func());
Item *predicate;
if (!is_function_of_type(item, Item_func::FT_FUNC)) {
Item *const item_zero = new (pc->mem_root) Item_int(0);
if (item_zero == nullptr) return nullptr;
predicate = new (pc->mem_root) Item_func_ne(item_zero, item);
predicate->marker = Item::MARKER_IMPLICIT_NE_ZERO;
} else {
predicate = new (pc->mem_root) Item_func_match_predicate(item);
}
return predicate;
}
/**
Contextualization for Item_cond functional items
Item_cond successors use Item_cond::list instead of Item_func::args
and Item_func::arg_count, so we can't itemize parse-time Item_cond
objects by forwarding a contextualization process to the parent Item_func
class: we need to overload this function to run a contextualization
the Item_cond::list items.
*/
bool Item_cond::do_itemize(Parse_context *pc, Item **res) {
if (skip_itemize(res)) return false;
if (super::do_itemize(pc, res)) return true;
List_iterator<Item> li(list);
Item *item;
while ((item = li++)) {
if (item->itemize(pc, &item)) return true;
if (!item->is_bool_func()) {
item = make_condition(pc, item);
if (item == nullptr) return true;
}
li.replace(item);
}
return false;
}
void Item_cond::copy_andor_arguments(THD *thd, Item_cond *item) {
List_iterator_fast<Item> li(item->list);
while (Item *it = li++) {
assert(it->real_item()); // Sanity check (no dangling 'ref')
list.push_back(it->copy_andor_structure(thd));
}
}
bool Item_cond::fix_fields(THD *thd, Item **ref) {
assert(!fixed);
List_iterator<Item> li(list);
Item *item;
Query_block *select = thd->lex->current_query_block();
auto func_type = functype();
assert(func_type == COND_AND_FUNC || func_type == COND_OR_FUNC);
// For semi-join flattening, indicate that we're traversing an AND, or an OR:
Condition_context CCT(select, func_type == COND_AND_FUNC
? enum_condition_context::ANDS
: enum_condition_context::ANDS_ORS);
uchar buff[sizeof(char *)]; // Max local vars in function
used_tables_cache = 0;
if (func_type == COND_AND_FUNC && ignore_unknown())
not_null_tables_cache = 0;
else
not_null_tables_cache = ~(table_map)0;
if (check_stack_overrun(thd, STACK_MIN_SIZE, buff))
return true; // Fatal error flag is set!
Item *new_item = nullptr;
bool remove_condition = false, can_remove_cond = true;
/*
The following optimization reduces the depth of an AND-OR tree.
E.g. a WHERE clause like
F1 AND (F2 AND (F2 AND F4))
is parsed into a tree with the same nested structure as defined
by braces. This optimization will transform such tree into
AND (F1, F2, F3, F4).
Trees of OR items are flattened as well:
((F1 OR F2) OR (F3 OR F4)) => OR (F1, F2, F3, F4)
Items for removed AND/OR levels will dangle until the death of the
entire statement.
The optimization is currently prepared statements and stored procedures
friendly as it doesn't allocate any memory and its effects are durable
(i.e. do not depend on PS/SP arguments).
*/
while ((item = li++)) {
Item_cond *cond;
while (item->type() == Item::COND_ITEM &&
(cond = down_cast<Item_cond *>(item)) &&
cond->functype() == func_type &&
!cond->list.is_empty()) { // Identical function
li.replace(cond->list);
cond->list.clear();
item = *li.ref(); // new current item
}
if (ignore_unknown()) item->apply_is_true();
// item can be substituted in fix_fields
if ((!item->fixed && item->fix_fields(thd, li.ref())) ||
(item = *li.ref())->check_cols(1))
return true; /* purecov: inspected */
/*
We optimize away the basic constant items here. If an AND condition
has "cond AND FALSE", then the entire condition is collapsed and
replaced with an ALWAYS FALSE item. Similarly, if an OR
condition has "cond OR TRUE", then the entire condition is replaced
with an ALWAYS TRUE item. Else only the const item is removed.
*/
/*
Make a note if the expression has been created by IN to EXISTS
transformation. If so we cannot remove the entire condition.
*/
if (item->created_by_in2exists()) {
remove_condition = false;
can_remove_cond = false;
}
/*
If it is indicated that we can remove the condition because
of a possible ALWAYS FALSE or ALWAYS TRUE condition, continue to
just call fix_fields on the items.
*/
if (remove_condition) continue;
/*
Do this optimization if fix_fields is allowed to change the condition
and if this is the first execution.
Check if the const item does not contain param's, SP args etc. We also
cannot optimize conditions if it's a view. The condition has to be a
top_level_item to get optimized as they can have only two return values,
true or false. A non-top_level_item can have true, false and NULL return.
Fulltext funcs cannot be removed as ftfunc_list stores the list
of pointers to these functions. The list gets accessed later
in the call to init_ftfuncs() from JOIN::reset.
TODO: Lift this restriction once init_ft_funcs gets moved to JOIN::exec
*/
if (ref != nullptr && select->first_execution && item->const_item() &&
!item->walk(&Item::is_non_const_over_literals, enum_walk::POSTFIX,
nullptr) &&
!thd->lex->is_view_context_analysis() && ignore_unknown() &&
!select->has_ft_funcs() && can_remove_cond) {
if (remove_const_conds(thd, item, &new_item)) return true;
/*
If a new_item is returned, indicate that all the items can be removed
from the list.
Else remove only the current element in the list.
*/
if (new_item != nullptr) {
remove_condition = true;
continue;
}
Cleanup_after_removal_context ctx(select);
item->walk(&Item::clean_up_after_removal, walk_options,
pointer_cast<uchar *>(&ctx));
li.remove();
continue;
}
// AND/OR take booleans
if (item->propagate_type(thd, MYSQL_TYPE_LONGLONG)) return true;
used_tables_cache |= item->used_tables();
if (func_type == COND_AND_FUNC && ignore_unknown())
not_null_tables_cache |= item->not_null_tables();
else
not_null_tables_cache &= item->not_null_tables();
add_accum_properties(item);
set_nullable(is_nullable() || item->is_nullable());
}
/*
Remove all the items from the list if it was indicated that we have
an ALWAYS TRUE or an ALWAYS FALSE condition. Replace with the new
TRUE or FALSE condition.
*/
if (remove_condition) {
new_item->fix_fields(thd, ref);
used_tables_cache = 0;
not_null_tables_cache = 0;
li.rewind();
while ((item = li++)) {
Cleanup_after_removal_context ctx(select);
item->walk(&Item::clean_up_after_removal, walk_options,
pointer_cast<uchar *>(&ctx));
li.remove();
}
const Prepared_stmt_arena_holder ps_arena_holder(thd);
list.push_front(new_item);
}
select->cond_count += list.elements;
if (resolve_type(thd)) return true;
fixed = true;
return false;
}
/**
Remove constant conditions over literals.
If an item is a trivial condition like a literal or an operation
on literal(s), we evaluate the item and based on the result, decide
if the entire condition can be replaced with an ALWAYS TRUE or
ALWAYS FALSE item.
For every constant condition, if the result is true, then
for an OR condition we return an ALWAYS TRUE item. For an AND
condition we return NULL if its not the only argument in the
condition.
If the result is false, for an AND condition we return
an ALWAYS FALSE item and for an OR condition we return NULL if
its not the only argument in the condition.
@param thd Current thread
@param item Item which needs to be evaluated
@param[out] new_item return new_item, if created
@return true, if error
false, on success
*/
bool Item_cond::remove_const_conds(THD *thd, Item *item, Item **new_item) {
assert(item->const_item());
const bool and_condition = functype() == Item_func::COND_AND_FUNC;
bool cond_value = true;
/* Push ignore / strict error handler */
Ignore_error_handler ignore_handler;
Strict_error_handler strict_handler;
if (thd->lex->is_ignore())
thd->push_internal_handler(&ignore_handler);
else if (thd->is_strict_mode())
thd->push_internal_handler(&strict_handler);
const bool err = eval_const_cond(thd, item, &cond_value);
/* Pop ignore / strict error handler */
if (thd->lex->is_ignore() || thd->is_strict_mode())
thd->pop_internal_handler();
if (err) return true;
if (cond_value) {
if (!and_condition || (argument_list()->elements == 1)) {
const Prepared_stmt_arena_holder ps_arena_holder(thd);
*new_item = new Item_func_true();
if (*new_item == nullptr) return true;
}
return false;
} else {
if (and_condition || (argument_list()->elements == 1)) {
const Prepared_stmt_arena_holder ps_arena_holder(thd);
*new_item = new Item_func_false();
if (*new_item == nullptr) return true;
}
return false;
}
}
void Item_cond::fix_after_pullout(Query_block *parent_query_block,
Query_block *removed_query_block) {
List_iterator<Item> li(list);
Item *item;
used_tables_cache = get_initial_pseudo_tables();
if (functype() == COND_AND_FUNC && ignore_unknown())
not_null_tables_cache = 0;
else
not_null_tables_cache = ~(table_map)0;
while ((item = li++)) {
item->fix_after_pullout(parent_query_block, removed_query_block);
used_tables_cache |= item->used_tables();
if (functype() == COND_AND_FUNC && ignore_unknown())
not_null_tables_cache |= item->not_null_tables();
else
not_null_tables_cache &= item->not_null_tables();
}
}
bool Item_cond::eq(const Item *item, bool binary_cmp) const {
if (this == item) return true;
if (item->type() != COND_ITEM) return false;
const Item_cond *item_cond = down_cast<const Item_cond *>(item);
if (functype() != item_cond->functype() ||
list.elements != item_cond->list.elements ||
strcmp(func_name(), item_cond->func_name()) != 0)
return false;
// Item_cond never uses "args". Inspect "list" instead.
assert(arg_count == 0 && item_cond->arg_count == 0);
return std::equal(list.begin(), list.end(), item_cond->list.begin(),
[binary_cmp](const Item &i1, const Item &i2) {
return ItemsAreEqual(&i1, &i2, binary_cmp);
});
}
bool Item_cond::walk(Item_processor processor, enum_walk walk, uchar *arg) {
if ((walk & enum_walk::PREFIX) && (this->*processor)(arg)) return true;
List_iterator_fast<Item> li(list);
Item *item;
while ((item = li++)) {
if (item->walk(processor, walk, arg)) return true;
}
return (walk & enum_walk::POSTFIX) && (this->*processor)(arg);
}
/**
Transform an Item_cond object with a transformer callback function.
The function recursively applies the transform method to each
member item of the condition list.
If the call of the method for a member item returns a new item
the old item is substituted for a new one.
After this the transformer is applied to the root node
of the Item_cond object.
*/
Item *Item_cond::transform(Item_transformer transformer, uchar *arg) {
List_iterator<Item> li(list);
Item *item;
while ((item = li++)) {
Item *new_item = item->transform(transformer, arg);
if (new_item == nullptr) return nullptr; /* purecov: inspected */
if (new_item != item) li.replace(new_item);
}
return Item_func::transform(transformer, arg);
}
/**
Compile Item_cond object with a processor and a transformer
callback functions.
First the function applies the analyzer to the root node of
the Item_func object. Then if the analyzer succeeeds (returns true)
the function recursively applies the compile method to member
item of the condition list.
If the call of the method for a member item returns a new item
the old item is substituted for a new one.
After this the transformer is applied to the root node
of the Item_cond object.
*/
Item *Item_cond::compile(Item_analyzer analyzer, uchar **arg_p,
Item_transformer transformer, uchar *arg_t) {
if (!(this->*analyzer)(arg_p)) return this;
List_iterator<Item> li(list);
Item *item;
while ((item = li++)) {
/*
The same parameter value of arg_p must be passed
to analyze any argument of the condition formula.
*/
uchar *arg_v = *arg_p;
Item *new_item = item->compile(analyzer, &arg_v, transformer, arg_t);
if (new_item == nullptr) return nullptr;
if (new_item != item) current_thd->change_item_tree(li.ref(), new_item);
}
// strange to call transform(): each argument will thus have the transformer
// called twice on it (in compile() above and Item_func::transform below)??
return Item_func::transform(transformer, arg_t);
}
void Item_cond::traverse_cond(Cond_traverser traverser, void *arg,
traverse_order order) {
List_iterator<Item> li(list);
Item *item;
switch (order) {
case (PREFIX):
(*traverser)(this, arg);
while ((item = li++)) {
item->traverse_cond(traverser, arg, order);
}
(*traverser)(nullptr, arg);
break;
case (POSTFIX):
while ((item = li++)) {
item->traverse_cond(traverser, arg, order);
}
(*traverser)(this, arg);
}
}
/**
Move SUM items out from item tree and replace with reference.
The split is done to get a unique item for each SUM function
so that we can easily find and calculate them.
(Calculation done by update_sum_func() and copy_sum_funcs() in
sql_select.cc)
@note
This function is run on all expression (SELECT list, WHERE, HAVING etc)
that have or refer (HAVING) to a SUM expression.
*/
bool Item_cond::split_sum_func(THD *thd, Ref_item_array ref_item_array,
mem_root_deque<Item *> *fields) {
List_iterator<Item> li(list);
Item *item;
while ((item = li++)) {
if (item->split_sum_func2(thd, ref_item_array, fields, li.ref(), true)) {
return true;
}
}
return false;
}
void Item_cond::update_used_tables() {
List_iterator_fast<Item> li(list);
Item *item;
used_tables_cache = 0;
m_accum_properties = 0;
if (functype() == COND_AND_FUNC && ignore_unknown())
not_null_tables_cache = 0;
else
not_null_tables_cache = ~(table_map)0;
while ((item = li++)) {
item->update_used_tables();
used_tables_cache |= item->used_tables();
add_accum_properties(item);
if (functype() == COND_AND_FUNC && ignore_unknown())
not_null_tables_cache |= item->not_null_tables();
else
not_null_tables_cache &= item->not_null_tables();
}
}
void Item_cond::print(const THD *thd, String *str,
enum_query_type query_type) const {
str->append('(');
bool first = true;
for (auto &item : list) {
if (!first) {
str->append(' ');
str->append(func_name());
str->append(' ');
}
item.print(thd, str, query_type);
first = false;
}
str->append(')');
}
bool Item_cond::truth_transform_arguments(THD *thd, Bool_test test) {
assert(test == BOOL_NEGATED);
List_iterator<Item> li(list);
Item *item;
while ((item = li++)) /* Apply not transformation to the arguments */
{
Item *new_item = item->truth_transformer(thd, test);
if (!new_item) {
if (!(new_item = new Item_func_not(item))) return true;
}
li.replace(new_item);
}
return false;
}
float Item_cond_and::get_filtering_effect(THD *thd, table_map filter_for_table,
table_map read_tables,
const MY_BITMAP *fields_to_ignore,
double rows_in_table) {
if (!(used_tables() & filter_for_table))
return COND_FILTER_ALLPASS; // No conditions below this apply to the table
float filter = COND_FILTER_ALLPASS;
List_iterator<Item> it(list);
Item *item;
/*
Calculated as "Conjunction of independent events":
P(A and B ...) = P(A) * P(B) * ...
*/
while ((item = it++))
filter *= item->get_filtering_effect(thd, filter_for_table, read_tables,
fields_to_ignore, rows_in_table);
return filter;
}
/**
Evaluation of AND(expr, expr, expr ...).
@note
abort_if_null is set for AND expressions for which we don't care if the
result is NULL or 0. This is set for:
- WHERE clause
- HAVING clause
- IF(expression)
@retval
1 If all expressions are true
@retval
0 If all expressions are false or if we find a NULL expression and
'abort_on_null' is set.
@retval
NULL if all expression are either 1 or NULL
*/
longlong Item_cond_and::val_int() {
assert(fixed);
List_iterator_fast<Item> li(list);
Item *item;
null_value = false;
while ((item = li++)) {
if (!item->val_bool()) {
if (ignore_unknown() || !(null_value = item->null_value))
return 0; // return false
}
if (current_thd->is_error()) return error_int();
}
return null_value ? 0 : 1;
}
float Item_cond_or::get_filtering_effect(THD *thd, table_map filter_for_table,
table_map read_tables,
const MY_BITMAP *fields_to_ignore,
double rows_in_table) {
if (!(used_tables() & filter_for_table))
return COND_FILTER_ALLPASS; // No conditions below this apply to the table
float filter = 0.0f;
List_iterator<Item> it(list);
Item *item;
while ((item = it++)) {
const float cur_filter = item->get_filtering_effect(
thd, filter_for_table, read_tables, fields_to_ignore, rows_in_table);
/*
Calculated as "Disjunction of independent events":
P(A or B) = P(A) + P(B) - P(A) * P(B)
If any of the ORed predicates has a filtering effect of
COND_FILTER_ALLPASS, the end result is COND_FILTER_ALLPASS. This is as
expected since COND_FILTER_ALLPASS means that a) the predicate has
no filtering effect at all, or b) the predicate's filtering
effect is unknown. In both cases, the only meaningful result is
for OR to produce COND_FILTER_ALLPASS.
*/
filter = filter + cur_filter - (filter * cur_filter);
}
return filter;
}
longlong Item_cond_or::val_int() {
assert(fixed);
List_iterator_fast<Item> li(list);
Item *item;
null_value = false;
while ((item = li++)) {
if (item->val_bool()) {
null_value = false;
return 1;
}
if (item->null_value) null_value = true;
if (current_thd->is_error()) return error_int();
}
return 0;
}
void Item_func_isnull::update_used_tables() {
args[0]->update_used_tables();
set_accum_properties(args[0]);
if (!args[0]->is_nullable()) {
used_tables_cache = 0;
} else {
used_tables_cache = args[0]->used_tables();
if (!const_item()) cache_used = false;
}
not_null_tables_cache = 0;
if (null_on_null && !const_item())
not_null_tables_cache |= args[0]->not_null_tables();
}
float Item_func_isnull::get_filtering_effect(THD *thd,
table_map filter_for_table,
table_map read_tables,
const MY_BITMAP *fields_to_ignore,
double rows_in_table) {
if (cache_used) {
return cached_value ? COND_FILTER_ALLPASS : 0.0f;
}
const Item_field *fld = contributes_to_filter(
thd, read_tables, filter_for_table, fields_to_ignore);
if (!fld) return COND_FILTER_ALLPASS;
const double selectivity = get_histogram_selectivity(
thd, *fld->field, histograms::enum_operator::IS_NULL, *this);
return selectivity == kUndefinedSelectivity
? fld->get_cond_filter_default_probability(rows_in_table,
COND_FILTER_EQUALITY)
: selectivity;
}
bool Item_func_isnull::fix_fields(THD *thd, Item **ref) {
if (super::fix_fields(thd, ref)) return true;
if (args[0]->type() == Item::FIELD_ITEM) {
Field *const field = down_cast<Item_field *>(args[0])->field;
/*
Fix to replace 'NULL' dates with '0' (shreeve@uci.edu)
See BUG#12594011
Documentation says that
SELECT datetime_notnull d FROM t1 WHERE d IS NULL
shall return rows where d=='0000-00-00'
Thus, for DATE and DATETIME columns defined as NOT NULL,
"date_notnull IS NULL" has to be modified to
"date_notnull IS NULL OR date_notnull == 0" (if outer join)
"date_notnull == 0" (otherwise)
It's a legacy convenience of the user, but it also causes problems as
it's not SQL-compliant. So, to keep it confined to the above type of
query only, we do not enable this behaviour when IS NULL
- is internally created (it must really mean IS NULL)
* IN-to-EXISTS creates IS NULL items but either they wrap Item_ref (so
the if() above skips them) or are not created if not nullable.
* fold_or_simplify() creates IS NULL items but not if not nullable.
- is not in WHERE (e.g. is in ON)
- isn't reachable from top of WHERE through a chain of AND
- is IS NOT NULL (Item_func_isnotnull doesn't use this fix_fields).
- is inside expressions (except the AND case above).
Moreover, we do this transformation at first resolution only, and
permanently. Indeed, at second resolution, it's not necessary and it would
even cause a problem (as we can't distinguish JOIN ON from WHERE
anymore).
*/
if (thd->lex->current_query_block()->resolve_place ==
Query_block::RESOLVE_CONDITION &&
thd->lex->current_query_block()->condition_context ==
enum_condition_context::ANDS &&
thd->lex->current_query_block()->first_execution &&
(field->type() == MYSQL_TYPE_DATE ||
field->type() == MYSQL_TYPE_DATETIME) &&
field->is_flag_set(NOT_NULL_FLAG)) {
const Prepared_stmt_arena_holder ps_arena_holder(thd);
Item *item0 = new Item_int(0);
if (item0 == nullptr) return true;
Item *new_cond = new Item_func_eq(args[0], item0);
if (new_cond == nullptr) return true;
if (args[0]->is_outer_field()) {
// outer join: transform "col IS NULL" to "col IS NULL or col=0"
new_cond = new Item_cond_or(new_cond, this);
if (new_cond == nullptr) return true;
} else {
// not outer join: transform "col IS NULL" to "col=0" (don't add the
// OR IS NULL part: it wouldn't change result but prevent index use)
}
*ref = new_cond;
return new_cond->fix_fields(thd, ref);
}
/*
Handles this special case for some ODBC applications:
They are requesting the row that was just updated with an auto_increment
value with this construct:
SELECT * FROM table_name WHERE auto_increment_column IS NULL
This will be changed to:
SELECT * FROM table_name WHERE auto_increment_column = LAST_INSERT_ID()
*/
if (thd->lex->current_query_block()->where_cond() == this &&
(thd->variables.option_bits & OPTION_AUTO_IS_NULL) != 0 &&
field->is_flag_set(AUTO_INCREMENT_FLAG) &&
!field->table->is_nullable()) {
const Prepared_stmt_arena_holder ps_arena_holder(thd);
const auto last_insert_id_func = new Item_func_last_insert_id();
if (last_insert_id_func == nullptr) return true;
*ref = new Item_func_eq(args[0], last_insert_id_func);
return *ref == nullptr || (*ref)->fix_fields(thd, ref);
}
}
return false;
}
bool Item_func_isnull::resolve_type(THD *thd) {
set_nullable(false);
if (Item_bool_func::resolve_type(thd)) return true;
cache_used = false;
if (!args[0]->is_nullable()) {
used_tables_cache = 0;
cached_value = false;
cache_used = true;
} else {
used_tables_cache = args[0]->used_tables();
// If const, remember if value is always NULL or never NULL
if (const_item() && !thd->lex->is_view_context_analysis()) {
cached_value = args[0]->is_null();
if (thd->is_error()) return true;
cache_used = true;
}
}
not_null_tables_cache = 0;
if (null_on_null && !const_item())
not_null_tables_cache |= args[0]->not_null_tables();
return false;
}
longlong Item_func_isnull::val_int() {
assert(fixed);
if (cache_used) return cached_value;
return args[0]->is_null() ? 1 : 0;
}
void Item_func_isnull::print(const THD *thd, String *str,
enum_query_type query_type) const {
str->append('(');
args[0]->print(thd, str, query_type);
str->append(STRING_WITH_LEN(" is null)"));
}
longlong Item_is_not_null_test::val_int() {
assert(fixed);
assert(used_tables_cache != 0);
DBUG_TRACE;
if (args[0]->is_null()) {
DBUG_PRINT("info", ("null"));
owner->m_was_null |= 1;
return 0;
} else
return 1;
}
bool Item_is_not_null_test::resolve_type(THD *thd) {
set_nullable(false);
if (Item_bool_func::resolve_type(thd)) return true;
not_null_tables_cache = 0;
if (null_on_null && !const_item())
not_null_tables_cache |= args[0]->not_null_tables();
return false;
}
void Item_is_not_null_test::update_used_tables() {
const table_map initial_pseudo_tables = get_initial_pseudo_tables();
used_tables_cache = initial_pseudo_tables;
args[0]->update_used_tables();
set_accum_properties(args[0]);
used_tables_cache |= args[0]->used_tables();
not_null_tables_cache = 0;
if (null_on_null) not_null_tables_cache |= args[0]->not_null_tables();
}
float Item_func_isnotnull::get_filtering_effect(
THD *thd, table_map filter_for_table, table_map read_tables,
const MY_BITMAP *fields_to_ignore, double rows_in_table) {
const Item_field *fld = contributes_to_filter(
thd, read_tables, filter_for_table, fields_to_ignore);
if (!fld) return COND_FILTER_ALLPASS;
const double selectivity = get_histogram_selectivity(
thd, *fld->field, histograms::enum_operator::IS_NOT_NULL, *this);
return selectivity == kUndefinedSelectivity
? 1.0f - fld->get_cond_filter_default_probability(
rows_in_table, COND_FILTER_EQUALITY)
: selectivity;
}
longlong Item_func_isnotnull::val_int() {
assert(fixed);
return args[0]->is_null() ? 0 : 1;
}
void Item_func_isnotnull::print(const THD *thd, String *str,
enum_query_type query_type) const {
str->append('(');
args[0]->print(thd, str, query_type);
str->append(STRING_WITH_LEN(" is not null)"));
}
float Item_func_like::get_filtering_effect(THD *thd, table_map filter_for_table,
table_map read_tables,
const MY_BITMAP *fields_to_ignore,
double rows_in_table) {
const Item_field *fld = contributes_to_filter(
thd, read_tables, filter_for_table, fields_to_ignore);
if (!fld) return COND_FILTER_ALLPASS;
/*
Filtering effect is similar to that of BETWEEN because
* "col like abc%" is similar to
"col between abc and abd"
The same applies for 'abc_'
* "col like %abc" can be seen as
"reverse(col) like cba%"" (see above)
* "col like "abc%def%..." is also similar
Now we're left with "col like <string_no_wildcards>" which should
have filtering effect like equality, but it would be costly to
look through the whole string searching for wildcards and since
LIKE is mostly used for wildcards this isn't checked.
*/
return fld->get_cond_filter_default_probability(rows_in_table,
COND_FILTER_BETWEEN);
}
longlong Item_func_like::val_int() {
assert(fixed);
if (!escape_evaluated && eval_escape_clause(current_thd)) return error_int();
const CHARSET_INFO *cs = cmp.cmp_collation.collation;
String *res = eval_string_arg(cs, args[0], &cmp.value1);
if (args[0]->null_value) {
null_value = true;
return 0;
}
String *res2 = eval_string_arg(cs, args[1], &cmp.value2);
if (args[1]->null_value) {
null_value = true;
return 0;
}
null_value = false;
if (current_thd->is_error()) return 0;
return my_wildcmp(cs, res->ptr(), res->ptr() + res->length(), res2->ptr(),
res2->ptr() + res2->length(), escape(),
(escape() == wild_one) ? -1 : wild_one,
(escape() == wild_many) ? -1 : wild_many)
? 0
: 1;
}
/**
We can optimize a where if first character isn't a wildcard
*/
Item_func::optimize_type Item_func_like::select_optimize(const THD *thd) {
/*
Can be called both during preparation (from prune_partitions()) and
optimization. Check if the pattern can be evaluated in the current phase.
*/
if (!args[1]->may_evaluate_const(thd)) return OPTIMIZE_NONE;
// Don't evaluate the pattern if evaluation during optimization is disabled.
if (!evaluate_during_optimization(args[1], thd->lex->current_query_block()))
return OPTIMIZE_NONE;
String *res2 = args[1]->val_str(&cmp.value2);
if (!res2) return OPTIMIZE_NONE;
if (!res2->length()) // Can optimize empty wildcard: column LIKE ''
return OPTIMIZE_OP;
assert(res2->ptr());
const char first = res2->ptr()[0];
return (first == wild_many || first == wild_one) ? OPTIMIZE_NONE
: OPTIMIZE_OP;
}
bool Item_func_like::check_covering_prefix_keys(THD *thd) {
Item *first_arg = args[0]->real_item();
Item *second_arg = args[1]->real_item();
if (first_arg->type() == Item::FIELD_ITEM) {
Field *field = down_cast<Item_field *>(first_arg)->field;
Key_map covering_keys = field->get_covering_prefix_keys();
if (covering_keys.is_clear_all()) return false;
if (second_arg->const_item()) {
size_t prefix_length = 0;
String *wild_str = second_arg->val_str(&cmp.value2);
if (thd->is_error()) return true;
if (second_arg->null_value) return false;
if (my_is_prefixidx_cand(wild_str->charset(), wild_str->ptr(),
wild_str->ptr() + wild_str->length(), escape(),
wild_many, &prefix_length))
field->table->update_covering_prefix_keys(field, prefix_length,
&covering_keys);
else
// Not comparing to a prefix, remove all prefix indexes
field->table->covering_keys.subtract(field->part_of_prefixkey);
} else
// Second argument is not a const
field->table->covering_keys.subtract(field->part_of_prefixkey);
}
return false;
}
bool Item_func_like::fix_fields(THD *thd, Item **ref) {
assert(!fixed);
args[0]->real_item()->set_can_use_prefix_key();
if (Item_bool_func::fix_fields(thd, ref)) {
return true;
}
return false;
}
void Item_func_like::cleanup() {
if (!escape_is_const) escape_evaluated = false;
Item_bool_func2::cleanup();
}
/**
Evaluate the expression in the escape clause.
@param thd thread handler
@return false on success, true on failure
*/
bool Item_func_like::eval_escape_clause(THD *thd) {
assert(!escape_evaluated);
escape_evaluated = true;
const bool no_backslash_escapes =
thd->variables.sql_mode & MODE_NO_BACKSLASH_ESCAPES;
// No ESCAPE clause is specified. The default escape character is backslash,
// unless NO_BACKSLASH_ESCAPES mode is enabled.
if (!escape_was_used_in_parsing()) {
m_escape = no_backslash_escapes ? 0 : '\\';
return false;
}
Item *escape_item = args[2];
String buf;
const String *escape_str = escape_item->val_str(&buf);
if (thd->is_error()) return true;
// Use backslash as escape character if the escape clause evaluates to NULL.
// (For backward compatibility. The SQL standard says the LIKE expression
// should evaluate to NULL in this case.)
if (escape_item->null_value) {
m_escape = '\\';
return false;
}
// An empty escape sequence means there is no escape character. An empty
// escape sequence is not accepted in NO_BACKSLASH_ESCAPES mode.
if (escape_str->is_empty()) {
if (no_backslash_escapes) {
my_error(ER_WRONG_ARGUMENTS, MYF(0), "ESCAPE");
return true;
}
m_escape = 0;
return false;
}
// Accept at most one character.
if (escape_str->numchars() > 1) {
my_error(ER_WRONG_ARGUMENTS, MYF(0), "ESCAPE");
return true;
}
const char *escape_str_ptr = escape_str->ptr();
// For multi-byte character sets, we store the Unicode code point of the
// escape character.
if (use_mb(cmp.cmp_collation.collation)) {
const CHARSET_INFO *cs = escape_str->charset();
my_wc_t wc;
int rc = cs->cset->mb_wc(
cs, &wc, pointer_cast<const uchar *>(escape_str_ptr),
pointer_cast<const uchar *>(escape_str_ptr) + escape_str->length());
if (rc <= 0) {
my_error(ER_WRONG_ARGUMENTS, MYF(0), "ESCAPE");
return true;
}
m_escape = wc;
return false;
}
// For single-byte character sets, we store the native code instead of the
// Unicode code point. The escape character is converted to the character set
// of the comparator if they differ.
const CHARSET_INFO *cs = cmp.cmp_collation.collation;
size_t unused;
if (escape_str->needs_conversion(escape_str->length(), escape_str->charset(),
cs, &unused)) {
char ch;
uint errors;
const size_t cnvlen =
copy_and_convert(&ch, 1, cs, escape_str_ptr, escape_str->length(),
escape_str->charset(), &errors);
if (cnvlen == 0) {
my_error(ER_WRONG_ARGUMENTS, MYF(0), "ESCAPE");
return true;
}
m_escape = static_cast<uchar>(ch);
} else {
m_escape = static_cast<uchar>(escape_str_ptr[0]);
}
return false;
}
void Item_func_like::print(const THD *thd, String *str,
enum_query_type query_type) const {
str->append('(');
args[0]->print(thd, str, query_type);
str->append(STRING_WITH_LEN(" like "));
args[1]->print(thd, str, query_type);
if (arg_count > 2) {
str->append(STRING_WITH_LEN(" escape "));
args[2]->print(thd, str, query_type);
}
str->append(')');
}
bool Item_func_xor::do_itemize(Parse_context *pc, Item **res) {
if (skip_itemize(res)) return false;
if (super::do_itemize(pc, res)) return true;
if (!args[0]->is_bool_func()) {
args[0] = make_condition(pc, args[0]);
if (args[0] == nullptr) return true;
}
if (!args[1]->is_bool_func()) {
args[1] = make_condition(pc, args[1]);
if (args[1] == nullptr) return true;
}
return false;
}
float Item_func_xor::get_filtering_effect(THD *thd, table_map filter_for_table,
table_map read_tables,
const MY_BITMAP *fields_to_ignore,
double rows_in_table) {
assert(arg_count == 2);
const float filter0 = args[0]->get_filtering_effect(
thd, filter_for_table, read_tables, fields_to_ignore, rows_in_table);
if (filter0 == COND_FILTER_ALLPASS) return COND_FILTER_ALLPASS;
const float filter1 = args[1]->get_filtering_effect(
thd, filter_for_table, read_tables, fields_to_ignore, rows_in_table);
if (filter1 == COND_FILTER_ALLPASS) return COND_FILTER_ALLPASS;
/*
Calculated as "exactly one of independent events":
P(A and not B) + P(B and not A) = P(A) + P(B) - 2 * P(A) * P(B)
*/
return filter0 + filter1 - (2 * filter0 * filter1);
}
/**
Make a logical XOR of the arguments.
If either operator is NULL, return NULL.
@todo
(low priority) Change this to be optimized as: @n
A XOR B -> (A) == 1 AND (B) <> 1) OR (A <> 1 AND (B) == 1) @n
To be able to do this, we would however first have to extend the MySQL
range optimizer to handle OR better.
@note
As we don't do any index optimization on XOR this is not going to be
very fast to use.
*/
longlong Item_func_xor::val_int() {
assert(fixed);
int result = 0;
null_value = false;
for (uint i = 0; i < arg_count; i++) {
result ^= (args[i]->val_int() != 0);
if (args[i]->null_value) {
null_value = true;
return 0;
}
if (current_thd->is_error()) return error_int();
}
return result;
}
/**
Apply NOT transformation to the item and return a new one.
Transform the item using next rules:
@verbatim
a AND b AND ... -> NOT(a) OR NOT(b) OR ...
a OR b OR ... -> NOT(a) AND NOT(b) AND ...
NOT(a) -> a
a = b -> a != b
a != b -> a = b
a < b -> a >= b
a >= b -> a < b
a > b -> a <= b
a <= b -> a > b
IS NULL(a) -> IS NOT NULL(a)
IS NOT NULL(a) -> IS NULL(a)
EXISTS(subquery) -> same EXISTS but with an internal mark of negation
IN(subquery) -> as above
@endverbatim
@return
New item or
NULL if we cannot apply NOT transformation (see Item::truth_transformer()).
*/
Item *Item_func_not::truth_transformer(THD *,
Bool_test test) // NOT(x) -> x
{
return (test == BOOL_NEGATED) ? args[0] : nullptr;
}
Item *Item_func_comparison::truth_transformer(THD *, Bool_test test) {
if (test != BOOL_NEGATED) return nullptr;
Item *item = negated_item();
return item;
}
/**
XOR can be negated by negating one of the operands:
NOT (a XOR b) => (NOT a) XOR b
=> a XOR (NOT b)
*/
Item *Item_func_xor::truth_transformer(THD *thd, Bool_test test) {
if (test != BOOL_NEGATED) return nullptr;
Item *neg_operand;
Item_func_xor *new_item;
if ((neg_operand = args[0]->truth_transformer(thd, test)))
// args[0] has truth_tranformer
new_item = new (thd->mem_root) Item_func_xor(neg_operand, args[1]);
else if ((neg_operand = args[1]->truth_transformer(thd, test)))
// args[1] has truth_tranformer
new_item = new (thd->mem_root) Item_func_xor(args[0], neg_operand);
else {
neg_operand = new (thd->mem_root) Item_func_not(args[0]);
new_item = new (thd->mem_root) Item_func_xor(neg_operand, args[1]);
}
return new_item;
}
/**
a IS NULL -> a IS NOT NULL.
*/
Item *Item_func_isnull::truth_transformer(THD *, Bool_test test) {
return (test == BOOL_NEGATED) ? new Item_func_isnotnull(args[0]) : nullptr;
}
/**
a IS NOT NULL -> a IS NULL.
*/
Item *Item_func_isnotnull::truth_transformer(THD *, Bool_test test) {
return (test == BOOL_NEGATED) ? new Item_func_isnull(args[0]) : nullptr;
}
Item *Item_cond_and::truth_transformer(THD *thd, Bool_test test)
// NOT(a AND b AND ...) -> NOT a OR NOT b OR ...
{
if (test != BOOL_NEGATED) return nullptr;
if (truth_transform_arguments(thd, test)) return nullptr;
Item *item = new Item_cond_or(list);
return item;
}
Item *Item_cond_or::truth_transformer(THD *thd, Bool_test test)
// NOT(a OR b OR ...) -> NOT a AND NOT b AND ...
{
if (test != BOOL_NEGATED) return nullptr;
if (truth_transform_arguments(thd, test)) return nullptr;
Item *item = new Item_cond_and(list);
return item;
}
Item *Item_func_nop_all::truth_transformer(THD *, Bool_test test) {
if (test != BOOL_NEGATED) return nullptr;
// "NOT (e $cmp$ ANY (SELECT ...)) -> e $rev_cmp$" ALL (SELECT ...)
Item_func_not_all *new_item = new Item_func_not_all(args[0]);
Item_allany_subselect *allany = down_cast<Item_allany_subselect *>(args[0]);
allany->m_func = allany->m_func_creator(false);
allany->m_all = !allany->m_all;
allany->m_upper_item = new_item;
return new_item;
}
Item *Item_func_not_all::truth_transformer(THD *, Bool_test test) {
if (test != BOOL_NEGATED) return nullptr;
// "NOT (e $cmp$ ALL (SELECT ...)) -> e $rev_cmp$" ANY (SELECT ...)
Item_func_nop_all *new_item = new Item_func_nop_all(args[0]);
Item_allany_subselect *allany = down_cast<Item_allany_subselect *>(args[0]);
allany->m_all = !allany->m_all;
allany->m_func = allany->m_func_creator(true);
allany->m_upper_item = new_item;
return new_item;
}
Item *Item_func_eq::negated_item() /* a = b -> a != b */
{
auto *i = new Item_func_ne(args[0], args[1]);
if (i != nullptr) i->marker = marker; // forward MARKER_IMPLICIT_NE_ZERO
return i;
}
Item *Item_func_ne::negated_item() /* a != b -> a = b */
{
auto *i = new Item_func_eq(args[0], args[1]);
if (i != nullptr) i->marker = marker; // forward MARKER_IMPLICIT_NE_ZERO
return i;
}
Item *Item_func_lt::negated_item() /* a < b -> a >= b */
{
return new Item_func_ge(args[0], args[1]);
}
Item *Item_func_ge::negated_item() /* a >= b -> a < b */
{
return new Item_func_lt(args[0], args[1]);
}
Item *Item_func_gt::negated_item() /* a > b -> a <= b */
{
return new Item_func_le(args[0], args[1]);
}
Item *Item_func_le::negated_item() /* a <= b -> a > b */
{
return new Item_func_gt(args[0], args[1]);
}
/**
just fake method, should never be called.
*/
Item *Item_func_comparison::negated_item() {
assert(0);
return nullptr;
}
bool Item_func_comparison::is_null() {
assert(args[0]->cols() == args[1]->cols());
// Fast path: If the operands are scalar, the result of the comparison is NULL
// if and only if at least one of the operands is NULL.
if (args[0]->cols() == 1) {
return (null_value = args[0]->is_null() || args[1]->is_null());
}
// If the operands are rows, we need to evaluate the comparison operator to
// find out if it is NULL. Fall back to the implementation in Item_func, which
// calls update_null_value() to evaluate the operator.
return Item_func::is_null();
}
bool Item_func_comparison::cast_incompatible_args(uchar *) {
return cmp.inject_cast_nodes();
}
Item_equal::Item_equal(Item_field *f1, Item_field *f2) : Item_bool_func() {
fields.push_back(f1);
fields.push_back(f2);
}
Item_equal::Item_equal(Item *c, Item_field *f) : Item_bool_func() {
fields.push_back(f);
m_const_arg = c;
compare_as_dates = f->is_temporal_with_date();
}
Item_equal::Item_equal(Item_equal *item_equal) : Item_bool_func() {
List_iterator_fast<Item_field> li(item_equal->fields);
Item_field *item;
while ((item = li++)) {
fields.push_back(item);
}
m_const_arg = item_equal->m_const_arg;
compare_as_dates = item_equal->compare_as_dates;
cond_false = item_equal->cond_false;
}
bool Item_equal::compare_const(THD *thd, Item *c) {
if (compare_as_dates) {
cmp.set_datetime_cmp_func(this, &c, &m_const_arg);
cond_false = cmp.compare();
} else {
Item_func_eq *func = new Item_func_eq(c, m_const_arg);
if (func == nullptr) return true;
if (func->set_cmp_func()) return true;
func->quick_fix_field();
cond_false = !func->val_int();
}
if (thd->is_error()) return true;
if (cond_false) used_tables_cache = 0;
return false;
}
bool Item_equal::add(THD *thd, Item *c, Item_field *f) {
if (cond_false) return false;
if (m_const_arg == nullptr) {
assert(f);
m_const_arg = c;
compare_as_dates = f->is_temporal_with_date();
return false;
}
return compare_const(thd, c);
}
bool Item_equal::add(THD *thd, Item *c) {
if (cond_false) return false;
if (m_const_arg == nullptr) {
m_const_arg = c;
return false;
}
return compare_const(thd, c);
}
void Item_equal::add(Item_field *f) { fields.push_back(f); }
uint Item_equal::members() { return fields.elements; }
/**
Check whether a field is referred in the multiple equality.
The function checks whether field is occurred in the Item_equal object .
@param field field whose occurrence is to be checked
@retval
true if multiple equality contains a reference to field
@retval
false otherwise
*/
bool Item_equal::contains(const Field *field) const {
for (const Item_field &item : fields) {
if (field->eq(item.field)) return true;
}
return false;
}
/**
Join members of another Item_equal object.
The function actually merges two multiple equalities.
After this operation the Item_equal object additionally contains
the field items of another item of the type Item_equal.
If the optional constant items are not equal the cond_false flag is
set to 1.
@param thd thread handler
@param item multiple equality whose members are to be joined
@returns false if success, true if error
*/
bool Item_equal::merge(THD *thd, Item_equal *item) {
fields.concat(&item->fields);
Item *c = item->m_const_arg;
if (c) {
/*
The flag cond_false will be set to 1 after this, if
the multiple equality already contains a constant and its
value is not equal to the value of c.
*/
if (add(thd, c)) return true;
}
cond_false |= item->cond_false;
if (cond_false) used_tables_cache = 0;
return false;
}
/**
Check appearance of new constant items in the multiple equality object.
The function checks appearance of new constant items among
the members of multiple equalities. Each new constant item is
compared with the designated constant item if there is any in the
multiple equality. If there is none the first new constant item
becomes designated.
@param thd thread handler
@returns false if success, true if error
*/
bool Item_equal::update_const(THD *thd) {
List_iterator<Item_field> it(fields);
Item *item;
while ((item = it++)) {
if (item->const_item() &&
/*
Don't propagate constant status of outer-joined column.
Such a constant status here is a result of:
a) empty outer-joined table: in this case such a column has a
value of NULL; but at the same time other arguments of
Item_equal don't have to be NULLs and the value of the whole
multiple equivalence expression doesn't have to be NULL or FALSE
because of the outer join nature;
or
b) outer-joined table contains only 1 row: the result of
this column is equal to a row field value *or* NULL.
Both values are inacceptable as Item_equal constants.
*/
!item->is_outer_field()) {
it.remove();
if (add(thd, item)) return true;
}
}
return false;
}
bool Item_equal::fix_fields(THD *thd, Item **) {
List_iterator_fast<Item_field> li(fields);
Item *item;
not_null_tables_cache = used_tables_cache = 0;
bool nullable = false;
while ((item = li++)) {
used_tables_cache |= item->used_tables();
not_null_tables_cache |= item->not_null_tables();
nullable |= item->is_nullable();
}
set_nullable(nullable);
if (resolve_type(thd)) return true;
fixed = true;
return false;
}
/**
Get filtering effect for multiple equalities, i.e.
"tx.col = value_1 = ... = value_n" where value_i may be a
constant, a column etc.
The multiple equality only contributes to the filtering effect for
'filter_for_table' if
a) A column in 'filter_for_table' is referred to
b) at least one value_i is a constant or a column in a table
already read
If this multiple equality refers to more than one column in
'filter_for_table', the predicates on all these fields will
contribute to the filtering effect.
*/
float Item_equal::get_filtering_effect(THD *thd, table_map filter_for_table,
table_map read_tables,
const MY_BITMAP *fields_to_ignore,
double rows_in_table) {
// This predicate does not refer to a column in 'filter_for_table'
if (!(used_tables() & filter_for_table)) return COND_FILTER_ALLPASS;
float filter = COND_FILTER_ALLPASS;
/*
Keep track of whether or not a usable value that is either a
constant or a column in an already read table has been found.
*/
bool found_comparable = false;
// Is there a constant that this multiple equality is equal to?
if (m_const_arg != nullptr) found_comparable = true;
List_iterator<Item_field> it(fields);
Item_field *cur_field;
/*
Calculate filtering effect for all applicable fields. If this
item has multiple fields from 'filter_for_table', each of these
fields will contribute to the filtering effect.
*/
while ((cur_field = it++)) {
if (cur_field->used_tables() & read_tables) {
// cur_field is a field in a table earlier in the join sequence.
found_comparable = true;
} else if (cur_field->used_tables() == filter_for_table) {
if (bitmap_is_set(fields_to_ignore, cur_field->field->field_index())) {
/*
cur_field is a field in 'filter_for_table', but it is a
field which already contributes to the filtering effect.
Its value can still be used as a constant if another column
in the same table is referred to in this multiple equality.
*/
found_comparable = true;
} else {
/*
cur_field is a field in 'filter_for_table', and it's not one
of the fields that must be ignored
*/
float cur_filter = cur_field->get_cond_filter_default_probability(
rows_in_table, COND_FILTER_EQUALITY);
// Use index statistics if available for this field
if (!cur_field->field->key_start.is_clear_all()) {
// cur_field is indexed - there may be statistics for it.
const TABLE *tab = cur_field->field->table;
for (uint j = 0; j < tab->s->keys; j++) {
if (cur_field->field->key_start.is_set(j) &&
tab->key_info[j].has_records_per_key(0)) {
cur_filter = static_cast<float>(
tab->key_info[j].records_per_key(0) / rows_in_table);
break;
}
}
/*
Since rec_per_key and rows_per_table are calculated at
different times, their values may not be in synch and thus
it is possible that cur_filter is greater than 1.0 if
rec_per_key is outdated. Force the filter to 1.0 in such
cases.
*/
if (cur_filter >= 1.0) cur_filter = 1.0f;
} else if (m_const_arg != nullptr) {
/*
If index statistics is not available, see if we can use any
available histogram statistics.
*/
const histograms::Histogram *histogram =
cur_field->field->table->find_histogram(
cur_field->field->field_index());
if (histogram != nullptr) {
std::array<Item *, 2> items{{cur_field, m_const_arg}};
double selectivity;
if (!histogram->get_selectivity(
items.data(), items.size(),
histograms::enum_operator::EQUALS_TO, &selectivity)) {
if (unlikely(thd->opt_trace.is_started())) {
Item_func_eq *eq_func =
new (thd->mem_root) Item_func_eq(cur_field, m_const_arg);
write_histogram_to_trace(thd, eq_func, selectivity);
}
cur_filter = static_cast<float>(selectivity);
}
}
}
filter *= cur_filter;
}
}
}
return found_comparable ? filter : COND_FILTER_ALLPASS;
}
void Item_equal::update_used_tables() {
List_iterator_fast<Item_field> li(fields);
Item *item;
not_null_tables_cache = used_tables_cache = 0;
if (cond_false) return;
m_accum_properties = 0;
while ((item = li++)) {
item->update_used_tables();
used_tables_cache |= item->used_tables();
not_null_tables_cache |= item->not_null_tables();
add_accum_properties(item);
}
if (m_const_arg != nullptr) used_tables_cache |= m_const_arg->used_tables();
}
longlong Item_equal::val_int() {
Item_field *item_field;
if (cond_false) return 0;
List_iterator_fast<Item_field> it(fields);
Item *item = m_const_arg != nullptr ? m_const_arg : it++;
eval_item->store_value(item);
if ((null_value = item->null_value)) return 0;
while ((item_field = it++)) {
/* Skip fields of non-const tables. They haven't been read yet */
if (item_field->field->table->const_table) {
const int rc = eval_item->cmp(item_field);
if ((rc == static_cast<int>(true)) || (null_value = (rc == UNKNOWN)))
return 0;
}
}
return 1;
}
Item_equal::~Item_equal() {
if (eval_item != nullptr) {
::destroy_at(eval_item);
eval_item = nullptr;
}
}
bool Item_equal::resolve_type(THD *thd) {
Item *item;
// As such item is created during optimization, types of members are known:
#ifndef NDEBUG
List_iterator_fast<Item_field> it(fields);
while ((item = it++)) {
assert(item->data_type() != MYSQL_TYPE_INVALID);
}
#endif
item = get_first();
eval_item = cmp_item::new_comparator(thd, item->result_type(), item,
item->collation.collation);
return eval_item == nullptr;
}
bool Item_equal::walk(Item_processor processor, enum_walk walk, uchar *arg) {
if ((walk & enum_walk::PREFIX) && (this->*processor)(arg)) return true;
List_iterator_fast<Item_field> it(fields);
Item *item;
while ((item = it++)) {
if (item->walk(processor, walk, arg)) return true;
}
return (walk & enum_walk::POSTFIX) && (this->*processor)(arg);
}
void Item_equal::print(const THD *thd, String *str,
enum_query_type query_type) const {
str->append(func_name());
str->append('(');
if (m_const_arg != nullptr) m_const_arg->print(thd, str, query_type);
bool first = (m_const_arg == nullptr);
for (auto &item_field : fields) {
if (!first) str->append(STRING_WITH_LEN(", "));
item_field.print(thd, str, query_type);
first = false;
}
str->append(')');
}
bool Item_equal::eq(const Item *item, bool binary_cmp) const {
if (!is_function_of_type(item, Item_func::MULT_EQUAL_FUNC)) {
return false;
}
const Item_equal *item_eq = down_cast<const Item_equal *>(item);
if ((m_const_arg != nullptr) != (item_eq->m_const_arg != nullptr)) {
return false;
}
if (m_const_arg != nullptr &&
!m_const_arg->eq(item_eq->m_const_arg, binary_cmp)) {
return false;
}
// NOTE: We assume there are no duplicates in either list.
if (fields.size() != item_eq->fields.size()) {
return false;
}
for (const Item_field &field : get_fields()) {
if (!item_eq->contains(field.field)) {
return false;
}
}
return true;
}
longlong Item_func_match_predicate::val_int() {
// Reimplement Item_func_match::val_int() instead of forwarding to it. Even
// though args[0] is usually an Item_func_match, it could in some situations
// be replaced with a reference to a field in a temporary table holding the
// result of the MATCH function. And since the conversion from double to
// integer in Field_double::val_int() is different from the conversion in
// Item_func_match::val_int(), just returning args[0]->val_int() would give
// wrong results when the argument has been materialized.
return args[0]->val_real() != 0;
}
longlong Item_func_trig_cond::val_int() {
if (trig_var == nullptr) {
// We don't use trigger conditions for IS_NOT_NULL_COMPL / FOUND_MATCH in
// the iterator executor (except for figuring out which conditions are join
// conditions and which are from WHERE), so we remove them whenever we can.
// However, we don't prune them entirely from the query tree, so they may be
// left within e.g. sub-conditions of ORs. Open up the conditions so
// that we don't have conditions that are disabled during execution.
assert(trig_type == IS_NOT_NULL_COMPL || trig_type == FOUND_MATCH);
return args[0]->val_int();
}
return *trig_var ? args[0]->val_int() : 1;
}
void Item_func_trig_cond::get_table_range(Table_ref **first_table,
Table_ref **last_table) const {
*first_table = nullptr;
*last_table = nullptr;
if (m_join == nullptr) return;
// There may be a JOIN_TAB or a QEP_TAB.
plan_idx last_inner;
if (m_join->qep_tab) {
QEP_TAB *qep_tab = &m_join->qep_tab[m_idx];
*first_table = qep_tab->table_ref;
last_inner = qep_tab->last_inner();
*last_table = m_join->qep_tab[last_inner].table_ref;
} else {
JOIN_TAB *join_tab = m_join->best_ref[m_idx];
*first_table = join_tab->table_ref;
last_inner = join_tab->last_inner();
*last_table = m_join->best_ref[last_inner]->table_ref;
}
}
table_map Item_func_trig_cond::get_inner_tables() const {
table_map inner_tables(0);
if (m_join != nullptr) {
if (m_join->qep_tab) {
const plan_idx last_idx = m_join->qep_tab[m_idx].last_inner();
plan_idx ix = m_idx;
do {
inner_tables |= m_join->qep_tab[ix++].table_ref->map();
} while (ix <= last_idx);
} else {
const plan_idx last_idx = m_join->best_ref[m_idx]->last_inner();
plan_idx ix = m_idx;
do {
inner_tables |= m_join->best_ref[ix++]->table_ref->map();
} while (ix <= last_idx);
}
}
return inner_tables;
}
void Item_func_trig_cond::print(const THD *thd, String *str,
enum_query_type query_type) const {
/*
Print:
<if>(<property><(optional list of source tables)>, condition, TRUE)
which means: if a certain property (<property>) is true, then return
the value of <condition>, else return TRUE. If source tables are
present, they are the owner of the property.
*/
str->append(func_name());
str->append("(");
switch (trig_type) {
case IS_NOT_NULL_COMPL:
str->append("is_not_null_compl");
break;
case FOUND_MATCH:
str->append("found_match");
break;
case OUTER_FIELD_IS_NOT_NULL:
str->append("outer_field_is_not_null");
break;
default:
assert(0);
}
if (m_join != nullptr) {
Table_ref *first_table, *last_table;
get_table_range(&first_table, &last_table);
str->append("(");
str->append(first_table->table->alias);
if (first_table != last_table) {
/* case of t1 LEFT JOIN (t2,t3,...): print range of inner tables */
str->append("..");
str->append(last_table->table->alias);
}
str->append(")");
}
str->append(", ");
args[0]->print(thd, str, query_type);
str->append(", true)");
}
/**
Get item that can be substituted for the supplied item.
@param field field item to get substitution field for, which must be
present within the multiple equality itself.
@retval Found substitution item in the multiple equality.
@details Get the first item of multiple equality that can be substituted
for the given field item. In order to make semijoin materialization strategy
work correctly we can't propagate equal fields between a materialized
semijoin and the outer query (or any other semijoin) unconditionally.
Thus the field is returned according to the following rules:
1) If the given field belongs to a materialized semijoin then the
first field in the multiple equality which belongs to the same semijoin
is returned.
2) If the given field doesn't belong to a materialized semijoin then
the first field in the multiple equality is returned.
*/
Item_field *Item_equal::get_subst_item(const Item_field *field) {
assert(field != nullptr);
const JOIN_TAB *field_tab = field->field->table->reginfo.join_tab;
/*
field_tab is NULL if this function was not called from
JOIN::optimize() but from e.g. mysql_delete() or mysql_update().
In these cases there is only one table and no semijoin
*/
if (field_tab && sj_is_materialize_strategy(field_tab->get_sj_strategy())) {
/*
It's a field from a materialized semijoin. We can substitute it only
with a field from the same semijoin.
Example: suppose we have a join_tab order:
ot1 ot2 <subquery> ot3 SJM(it1 it2 it3)
<subquery> is the temporary table that is materialized from the join
of it1, it2 and it3.
and equality ot2.col = <subquery>.col = it1.col = it2.col
If we're looking for best substitute for 'it2.col', we must pick it1.col
and not ot2.col. it2.col is evaluated while performing materialization,
when the outer tables are not available in the execution.
Note that subquery materialization does not have the same problem:
even though IN->EXISTS has injected equalities involving outer query's
expressions, it has wrapped those expressions in variants of Item_ref,
never Item_field, so they can be part of an Item_equal only if they are
constant (in which case there is no problem with choosing them below);
@see check_simple_equality().
*/
List_iterator<Item_field> it(fields);
Item_field *item;
const plan_idx first = field_tab->first_sj_inner(),
last = field_tab->last_sj_inner();
while ((item = it++)) {
const plan_idx idx = item->field->table->reginfo.join_tab->idx();
if (idx >= first && idx <= last) return item;
}
} else {
/*
The field is not in a materialized semijoin nest. We can return
the first field in the multiple equality.
Example: suppose we have a join_tab order with MaterializeLookup:
ot1 ot2 <subquery> SJM(it1 it2)
Here we should always pick the first field in the multiple equality,
as this will be present before all other dependent fields.
Example: suppose we have a join_tab order with MaterializeScan:
<subquery> ot1 ot2 SJM(it1 it2)
and equality <subquery>.col = ot2.col = ot1.col = it2.col.
When looking for best substitute for ot2.col, we should pick
<subquery>.col, because column values from the inner materialized tables
are copied to the temporary table <subquery>, and when we run the scan,
field values are read into this table's field buffers.
*/
return fields.head();
}
assert(false); // Should never get here.
return nullptr;
}
/**
Transform an Item_equal object after having added a table that
represents a materialized semi-join.
@details
If the multiple equality represented by the Item_equal object contains
a field from the subquery that was used to create the materialized table,
add the corresponding key field from the materialized table to the
multiple equality.
@see JOIN::update_equalities_for_sjm() for the reason.
*/
Item *Item_equal::equality_substitution_transformer(uchar *arg) {
Table_ref *sj_nest = reinterpret_cast<Table_ref *>(arg);
List_iterator<Item_field> it(fields);
List<Item_field> added_fields;
Item_field *item;
// Iterate over the fields in the multiple equality
while ((item = it++)) {
// Skip fields that do not come from materialized subqueries
const JOIN_TAB *tab = item->field->table->reginfo.join_tab;
if (!tab || !sj_is_materialize_strategy(tab->get_sj_strategy())) continue;
// Iterate over the fields selected from the subquery
uint fieldno = 0;
for (Item *existing : sj_nest->nested_join->sj_inner_exprs) {
if (existing->real_item()->eq(item, false))
added_fields.push_back(sj_nest->nested_join->sjm.mat_fields[fieldno]);
fieldno++;
}
}
fields.concat(&added_fields);
return this;
}
/**
Replace arg of Item_func_eq object after having added a table that
represents a materialized semi-join.
@details
The right argument of an injected semi-join equality (which comes from
the select list of the subquery) is replaced with the corresponding
column from the materialized temporary table, if the left and right
arguments are not from the same semi-join nest.
@see JOIN::update_equalities_for_sjm() for why this is needed.
*/
Item *Item_func_eq::equality_substitution_transformer(uchar *arg) {
Table_ref *sj_nest = reinterpret_cast<Table_ref *>(arg);
// Skip if equality can be processed during materialization
if (((used_tables() & ~INNER_TABLE_BIT) & ~sj_nest->sj_inner_tables) == 0) {
return this;
}
// Iterate over the fields selected from the subquery
uint fieldno = 0;
for (Item *existing : sj_nest->nested_join->sj_inner_exprs) {
if (existing->real_item()->eq(args[1], false) &&
(args[0]->used_tables() & ~sj_nest->sj_inner_tables))
current_thd->change_item_tree(
args + 1, sj_nest->nested_join->sjm.mat_fields[fieldno]);
fieldno++;
}
return this;
}
float Item_func_eq::get_filtering_effect(THD *thd, table_map filter_for_table,
table_map read_tables,
const MY_BITMAP *fields_to_ignore,
double rows_in_table) {
if (arguments()[0]->type() == NULL_ITEM ||
arguments()[1]->type() == NULL_ITEM) {
return 0.0;
}
const Item_field *fld = contributes_to_filter(
thd, read_tables, filter_for_table, fields_to_ignore);
if (!fld) return COND_FILTER_ALLPASS;
return GetEqualSelectivity(thd, this, *fld, rows_in_table);
}
bool Item_func_any_value::aggregate_check_group(uchar *arg) {
Group_check *gc = reinterpret_cast<Group_check *>(arg);
if (gc->is_stopped(this)) return false;
gc->stop_at(this);
return false;
}
bool Item_func_any_value::aggregate_check_distinct(uchar *arg) {
Distinct_check *dc = reinterpret_cast<Distinct_check *>(arg);
if (dc->is_stopped(this)) return false;
dc->stop_at(this);
return false;
}
bool Item_func_any_value::collect_item_field_or_view_ref_processor(uchar *arg) {
Collect_item_fields_or_view_refs *info =
pointer_cast<Collect_item_fields_or_view_refs *>(arg);
if (m_phase_post) {
m_phase_post = false;
info->m_any_value_level--;
} else {
m_phase_post = true;
info->m_any_value_level++;
}
return false;
}
bool Item_cond_and::contains_only_equi_join_condition() const {
for (const Item &item : list) {
if (item.type() != Item::FUNC_ITEM) {
return false;
}
const Item_func *item_func = down_cast<const Item_func *>(&item);
if (!item_func->contains_only_equi_join_condition()) {
return false;
}
}
return true;
}
bool Item_eq_base::contains_only_equi_join_condition() const {
assert(arg_count == 2);
Item *left_arg = args[0];
Item *right_arg = args[1];
const table_map left_arg_used_tables =
left_arg->used_tables() & ~PSEUDO_TABLE_BITS;
const table_map right_arg_used_tables =
right_arg->used_tables() & ~PSEUDO_TABLE_BITS;
if (left_arg_used_tables == 0 || right_arg_used_tables == 0) {
// This is a filter, and not a join condition.
return false;
}
// We may have conditions like (t1.x = t1.y + t2.x) which cannot be used as an
// equijoin condition because t1 is referenced on both sides of the equality.
if (Overlaps(left_arg_used_tables, right_arg_used_tables)) {
return false;
}
// We may have view references which are constants in the underlying
// derived tables but used_tables() might not reflect it because the
// merged derived table is an inner table of an outer join
// (Item_view_ref::used_tables()). Considering conditions having these
// constants as equi-join conditions is causing problems for secondary
// engine. So for now, we reject these.
if (left_arg->type() == Item::REF_ITEM &&
down_cast<Item_ref *>(left_arg)->ref_type() == Item_ref::VIEW_REF &&
down_cast<Item_ref *>(left_arg)->ref_item()->used_tables() == 0)
return false;
if (right_arg->type() == Item::REF_ITEM &&
down_cast<Item_ref *>(right_arg)->ref_type() == Item_ref::VIEW_REF &&
down_cast<Item_ref *>(right_arg)->ref_item()->used_tables() == 0)
return false;
return true;
}
bool Item_func_trig_cond::contains_only_equi_join_condition() const {
if (args[0]->item_name.ptr() == antijoin_null_cond) {
return true;
}
if (args[0]->type() != Item::FUNC_ITEM &&
args[0]->type() != Item::COND_ITEM) {
return false;
}
return down_cast<const Item_func *>(args[0])
->contains_only_equi_join_condition();
}
// Append a string value to join_key_buffer, extracted from "comparand".
// In general, we append the sort key from the Item, which makes it memcmp-able.
//
// For strings with NO_PAD collations, we also prepend the string value with the
// number of bytes written to the buffer if "is_multi_column_key" is true. This
// is needed when the join key consists of multiple columns. Otherwise, we would
// get the same join key for ('abc', 'def') and ('ab', 'cdef'), so that a join
// condition such as
//
// t1.a = t2.a AND t1.b = t2.b
//
// would degenerate to
//
// CONCAT(t1.a, t2.a) = CONCAT(t1.b, t2.b)
//
static bool append_string_value(Item *comparand,
const CHARSET_INFO *character_set,
size_t max_char_length,
bool pad_char_to_full_length,
bool is_multi_column_key,
String *join_key_buffer) {
// String results must be extracted using the correct character set and
// collation. This is given by the Arg_comparator, so we call strnxfrm
// to make the string values memcmp-able.
StringBuffer<STRING_BUFFER_USUAL_SIZE> str_buffer;
String *str = eval_string_arg(character_set, comparand, &str_buffer);
if (comparand->null_value || str == nullptr) {
return true;
}
// If the collation is a PAD SPACE collation, use the pre-calculated max
// length so that the shortest string is padded to the same length as the
// longest string. We also do the same for the special case where the
// (deprecated) SQL mode PAD_CHAR_TO_FULL_LENGTH is enabled, where CHAR
// columns are padded to full length regardless of the collation used.
// The longest possible string is given by the data type length specification
// (CHAR(N), VARCHAR(N)).
const bool use_padding =
character_set->pad_attribute == PAD_SPACE ||
(comparand->data_type() == MYSQL_TYPE_STRING && pad_char_to_full_length);
const size_t char_length = use_padding ? max_char_length : str->numchars();
const size_t buffer_size = character_set->coll->strnxfrmlen(
character_set, char_length * character_set->mbmaxlen);
// If we don't pad strings, we need to include the length of the string when
// we have multi-column keys, so that it's unambiguous where the string ends
// and where the next part of the key begins in case of multi-column join
// keys. Reserve space for it here.
const bool prepend_length = !use_padding && is_multi_column_key;
using KeyLength = std::uint32_t;
const size_t orig_buffer_size = join_key_buffer->length();
if (prepend_length) {
if (join_key_buffer->reserve(sizeof(KeyLength))) {
return true;
}
join_key_buffer->length(orig_buffer_size + sizeof(KeyLength));
}
if (buffer_size > 0) {
// Reserve space in the buffer so we can insert the transformed string
// directly into the buffer.
if (join_key_buffer->reserve(buffer_size)) {
return true;
}
uchar *dptr = pointer_cast<uchar *>(join_key_buffer->ptr()) +
join_key_buffer->length();
const size_t actual_length =
my_strnxfrm(character_set, dptr, buffer_size,
pointer_cast<const uchar *>(str->ptr()), str->length());
assert(actual_length <= buffer_size);
// Increase the length of the buffer by the actual length of the
// string transformation.
join_key_buffer->length(join_key_buffer->length() + actual_length);
}
if (prepend_length) {
const KeyLength key_length =
join_key_buffer->length() - (orig_buffer_size + sizeof(KeyLength));
memcpy(join_key_buffer->ptr() + orig_buffer_size, &key_length,
sizeof(key_length));
}
return false;
}
// Append a double value to join_key_buffer.
static bool append_double_value(double value, bool is_null,
String *join_key_buffer) {
if (is_null) return true;
join_key_buffer->append(pointer_cast<const char *>(&value), sizeof(value),
static_cast<size_t>(0));
return false;
}
// Append an integer value to join_key_buffer.
// Storing an extra byte for unsigned_flag ensures that negative values do not
// match large unsigned values.
static bool append_int_value(longlong value, bool is_null, bool unsigned_flag,
String *join_key_buffer) {
if (is_null) return true;
join_key_buffer->append(pointer_cast<const char *>(&value), sizeof(value),
static_cast<size_t>(0));
// We do not need the extra byte for (0 <= value <= LLONG_MAX).
if (value < 0) join_key_buffer->append(static_cast<char>(unsigned_flag));
return false;
}
static bool append_hash_for_string_value(Item *comparand,
const CHARSET_INFO *character_set,
String *join_key_buffer) {
StringBuffer<STRING_BUFFER_USUAL_SIZE> str_buffer;
String *str = eval_string_arg(character_set, comparand, &str_buffer);
if (str == nullptr) {
return true;
}
// nr2 isn't used; we only need one, and some collations don't even
// update it. The seeds are 1 and 4 by convention.
uint64 nr1 = 1, nr2 = 4;
character_set->coll->hash_sort(character_set,
pointer_cast<const uchar *>(str->ptr()),
str->length(), &nr1, &nr2);
join_key_buffer->reserve(sizeof(nr1));
uchar *dptr =
pointer_cast<uchar *>(join_key_buffer->ptr()) + join_key_buffer->length();
memcpy(dptr, &nr1, sizeof(nr1));
join_key_buffer->length(join_key_buffer->length() + sizeof(nr1));
return false;
}
static bool append_hash_for_json_value(Item *comparand,
String *join_key_buffer) {
Json_wrapper value;
StringBuffer<STRING_BUFFER_USUAL_SIZE> buffer1, buffer2;
if (get_json_atom_wrapper(
&comparand, /*arg_idx=*/0, /*calling_function=*/"hash", &buffer1,
&buffer2, &value, /*scalar=*/nullptr, /*accept_string=*/true)) {
return true;
}
if (comparand->null_value) return true;
const uint64_t hash = value.make_hash_key(/*hash_val=*/0);
return join_key_buffer->append(pointer_cast<const char *>(&hash),
sizeof(hash));
}
// Append a decimal value to join_key_buffer, extracted from "comparand".
//
// The number of bytes written depends on the actual value. (Leading zero digits
// are stripped off, and for +/- 0 even trailing zeros are stripped off.) In
// order to prevent ambiguity in case of multi-column join keys, the length in
// bytes is prepended to the value if "is_multi_column_key" is true.
static bool append_decimal_value(Item *comparand, bool is_multi_column_key,
String *join_key_buffer) {
my_decimal decimal_buffer;
const my_decimal *decimal = comparand->val_decimal(&decimal_buffer);
if (comparand->null_value) {
return true;
}
if (decimal_is_zero(decimal)) {
// Encode zero as an empty string. Write length = 0 to indicate that.
if (is_multi_column_key) {
if (join_key_buffer->append(char{0})) {
return true;
}
}
return false;
}
// Normalize the precision to get same hash length for equal numbers.
const int scale = decimal->frac;
const int precision = my_decimal_intg(decimal) + scale;
const int buffer_size = my_decimal_get_binary_size(precision, scale);
if (join_key_buffer->reserve(buffer_size + 1)) {
return true;
}
if (is_multi_column_key) {
join_key_buffer->append(static_cast<char>(buffer_size));
}
uchar *write_position =
pointer_cast<uchar *>(join_key_buffer->ptr()) + join_key_buffer->length();
my_decimal2binary(E_DEC_FATAL_ERROR, decimal, write_position, precision,
scale);
join_key_buffer->length(join_key_buffer->length() + buffer_size);
return false;
}
/// Extract the value from the item and append it to the output buffer
/// "join_key_buffer" in a memcmp-able format.
///
/// The value extracted here will be used as the key in the hash table
/// structure, where comparisons between keys are based on memcmp. Thus, it is
/// important that the values extracted are memcmp-able, so for string values,
/// we are basically creating a sort key. Other types (DECIMAL and FLOAT(M,N)
/// and DOUBLE(M, N)) may be wrapped in a typecast in order to get a memcmp-able
/// format from both sides of the condition.
/// See Item_eq_base::create_cast_if_needed for more details.
///
/// @param thd the thread handler
/// @param join_condition The hash join condition from which to get the value
/// to write into the buffer.
/// @param comparator the comparator set up by Item_cmpfunc. This gives us the
/// context in which the comparison is done. It is also needed for extracting
/// the value in case of DATE/TIME/DATETIME/YEAR values in some cases
/// @param is_left_argument whether or not the provided item is the left
/// argument of the condition. This is needed in case the comparator has set
/// up a custom function for extracting the value from the item, as there are
/// two separate functions for each side of the condition
/// @param is_multi_column_key true if the hash join key has multiple columns
/// (that is, the hash join condition is a conjunction)
/// @param[out] join_key_buffer the output buffer where the extracted value
/// is appended
///
/// @returns true if a SQL NULL value was found
static bool extract_value_for_hash_join(THD *thd,
const HashJoinCondition &join_condition,
const Arg_comparator *comparator,
bool is_left_argument,
bool is_multi_column_key,
String *join_key_buffer) {
if (comparator->get_compare_type() == ROW_RESULT) {
// If the comparand returns a row via a subquery or a row value expression,
// the comparator will be set up with child comparators (one for each column
// in the row value). For hash join, we currently allow row values with only
// one column.
assert(comparator->get_child_comparator_count() == 1);
comparator = comparator->get_child_comparators();
}
Item *comparand = is_left_argument ? join_condition.left_extractor()
: join_condition.right_extractor();
if (comparand->type() == Item::ROW_ITEM) {
// In case of row value, get hold of the first column in the row. Note that
// this is not needed for subqueries; val_* will execute and return the
// value for scalar subqueries.
comparand = comparand->element_index(0);
}
if (comparator->use_custom_value_extractors()) {
// The Arg_comparator has decided that the values should be extracted using
// the function pointer given by "get_value_[a|b]_func", so let us do the
// same. This can happen for DATE, DATETIME and YEAR, and there are separate
// function pointers for each side of the argument.
bool is_null;
longlong value = comparator->extract_value_from_argument(
thd, comparand, is_left_argument, &is_null);
if (is_null) {
return true;
}
join_key_buffer->append(pointer_cast<const char *>(&value), sizeof(value),
static_cast<size_t>(0));
return false;
}
switch (comparator->get_compare_type()) {
case STRING_RESULT: {
if (comparator->compare_as_json()) {
// JSON values can be large, so we don't store the full sort key.
assert(!join_condition.store_full_sort_key());
return append_hash_for_json_value(comparand, join_key_buffer);
}
if (join_condition.store_full_sort_key()) {
return append_string_value(
comparand, comparator->cmp_collation.collation,
join_condition.max_character_length(),
(thd->variables.sql_mode & MODE_PAD_CHAR_TO_FULL_LENGTH) > 0,
is_multi_column_key, join_key_buffer);
} else {
return append_hash_for_string_value(
comparand, comparator->cmp_collation.collation, join_key_buffer);
}
}
case REAL_RESULT: {
double value = comparand->val_real();
if (value == 0.0) value = 0.0; // Ensure that -0.0 hashes as +0.0.
return append_double_value(value, comparand->null_value, join_key_buffer);
}
case INT_RESULT: {
const longlong value = comparand->val_int();
return append_int_value(value, comparand->null_value,
comparand->unsigned_flag, join_key_buffer);
}
case DECIMAL_RESULT: {
return append_decimal_value(comparand, is_multi_column_key,
join_key_buffer);
}
default: {
// This should not happen.
assert(false);
return true;
}
}
return false;
}
bool Item_eq_base::append_join_key_for_hash_join(
THD *thd, const table_map tables, const HashJoinCondition &join_condition,
bool is_multi_column_key, String *join_key_buffer) const {
const bool is_left_argument = join_condition.left_uses_any_table(tables);
assert(is_left_argument != join_condition.right_uses_any_table(tables));
// If this is a NULL-safe equal (<=>), we need to store NULL values in the
// hash key. Set it to zero initially to indicate not NULL. Gets updated later
// if it turns out the value is NULL.
const size_t null_pos = join_key_buffer->length();
if (join_condition.null_equals_null()) {
join_key_buffer->append(char{0});
}
const bool is_null =
extract_value_for_hash_join(thd, join_condition, &cmp, is_left_argument,
is_multi_column_key, join_key_buffer);
if (is_null && join_condition.null_equals_null()) {
(*join_key_buffer)[null_pos] = 1;
return false;
}
return is_null;
}
Item *Item_eq_base::create_cast_if_needed(MEM_ROOT *mem_root,
Item *argument) const {
// We wrap the argument in a typecast node in two cases:
// a) If the comparison is done in a DECIMAL context.
// b) If the comparison is done in a floating point context, AND both sides
// have a data type where the number of decimals is specified. Note that
// specifying the numbers of decimals for floating point types is
// deprecated, so this should be a really rare case.
//
// In both cases, we cast the argument to a DECIMAL, where the precision and
// scale is the highest among the condition arguments.
const bool cast_to_decimal = cmp.get_compare_type() == DECIMAL_RESULT ||
(cmp.get_compare_type() == REAL_RESULT &&
args[0]->decimals < DECIMAL_NOT_SPECIFIED &&
args[1]->decimals < DECIMAL_NOT_SPECIFIED);
if (cast_to_decimal) {
const int precision =
max(args[0]->decimal_precision(), args[1]->decimal_precision());
const int scale = max(args[0]->decimals, args[1]->decimals);
return new (mem_root)
Item_typecast_decimal(POS(), argument, precision, scale);
}
return argument;
}
HashJoinCondition::HashJoinCondition(Item_eq_base *join_condition,
MEM_ROOT *mem_root)
: m_join_condition(join_condition),
m_left_extractor(join_condition->create_cast_if_needed(
mem_root, join_condition->arguments()[0])),
m_right_extractor(join_condition->create_cast_if_needed(
mem_root, join_condition->arguments()[1])),
m_left_used_tables(join_condition->arguments()[0]->used_tables()),
m_right_used_tables(join_condition->arguments()[1]->used_tables()),
m_max_character_length(max(m_left_extractor->max_char_length(),
m_right_extractor->max_char_length())),
m_null_equals_null(join_condition->functype() == Item_func::EQUAL_FUNC &&
(join_condition->get_arg(0)->is_nullable() ||
join_condition->get_arg(1)->is_nullable())) {
m_store_full_sort_key = true;
const bool using_secondary_storage_engine =
(current_thd->lex->m_sql_cmd != nullptr &&
current_thd->lex->m_sql_cmd->using_secondary_storage_engine());
if ((join_condition->compare_type() == STRING_RESULT ||
join_condition->compare_type() == ROW_RESULT) &&
!using_secondary_storage_engine) {
const CHARSET_INFO *cs = join_condition->compare_collation();
if (cs->coll->strnxfrmlen(cs, cs->mbmaxlen * m_max_character_length) >
1024) {
// This field can potentially get very long keys; it is better to
// just store the hash, and then re-check the condition afterwards.
// The value of 1024 is fairly arbitrary, and may be changed in the
// future. We don't do this for secondary engines; how they wish
// to do their hash joins will be an internal implementation detail.
m_store_full_sort_key = false;
}
}
}
longlong Arg_comparator::extract_value_from_argument(THD *thd, Item *item,
bool left_argument,
bool *is_null) const {
assert(use_custom_value_extractors());
assert(get_value_a_func != nullptr && get_value_b_func != nullptr);
// The Arg_comparator has decided that the values should be extracted using
// the function pointer given by "get_value_[a|b]_func", so let us do the
// same. This can happen for DATE, DATETIME and YEAR, and there are separate
// function pointers for each side of the argument.
Item **item_arg = &item;
if (left_argument) {
return get_value_a_func(thd, &item_arg, nullptr, item, is_null);
} else {
return get_value_b_func(thd, &item_arg, nullptr, item, is_null);
}
}
void find_and_adjust_equal_fields(Item *item, table_map available_tables,
bool replace, bool *found) {
WalkItem(item, enum_walk::PREFIX,
[available_tables, replace, found](Item *inner_item) {
if (inner_item->type() == Item::FUNC_ITEM) {
Item_func *func_item = down_cast<Item_func *>(inner_item);
for (uint i = 0; i < func_item->arg_count; ++i) {
if (func_item->arguments()[i]->type() == Item::FIELD_ITEM) {
func_item->arguments()[i] = FindEqualField(
down_cast<Item_field *>(func_item->arguments()[i]),
available_tables, replace, found);
if (*found == false && !replace) return true;
}
}
}
return false;
});
}
static void ensure_multi_equality_fields_are_available(
Item **args, int arg_idx, table_map available_tables, bool replace,
bool *found) {
if (args[arg_idx]->type() == Item::FIELD_ITEM) {
// The argument we want to find and adjust is an Item_field. Create a
// new Item_field with a field that is reachable if "replace" is
// set to true. Else, set "found" to true if a field is found.
args[arg_idx] = FindEqualField(down_cast<Item_field *>(args[arg_idx]),
available_tables, replace, found);
} else {
// The argument is not a field item. Walk down the item tree and see if we
// find any Item_field that needs adjustment.
find_and_adjust_equal_fields(args[arg_idx], available_tables, replace,
found);
}
}
void Item_func_eq::ensure_multi_equality_fields_are_available(
table_map left_side_tables, table_map right_side_tables, bool replace,
bool *found) {
const table_map left_arg_used_tables = args[0]->used_tables();
const table_map right_arg_used_tables = args[1]->used_tables();
if (left_arg_used_tables == 0 || right_arg_used_tables == 0) {
// This is a filter, not a join condition.
*found = false;
return;
}
if (IsSubset(left_arg_used_tables, left_side_tables) &&
IsSubset(right_arg_used_tables, right_side_tables)) {
// The left argument matches the left side tables, and the
// right one to the right side tables. This can stay
// on this join.
*found = true;
} else if (IsSubset(left_arg_used_tables, right_side_tables) &&
IsSubset(right_arg_used_tables, left_side_tables)) {
// The left argument matches the right side tables, and the
// right one to the left side tables. This can stay
// on this join.
*found = true;
} else if (IsSubset(left_arg_used_tables, left_side_tables) &&
!IsSubset(right_arg_used_tables, right_side_tables)) {
// The left argument matches the left side tables, so find an
// "equal" field from right side tables. Adjust the right side
// with the equal field if "replace" is set to true.
::ensure_multi_equality_fields_are_available(
args, /*arg_idx=*/1, right_side_tables, replace, found);
} else if (IsSubset(left_arg_used_tables, right_side_tables) &&
!IsSubset(right_arg_used_tables, left_side_tables)) {
// The left argument matches the right side tables, so find an
// "equal" field from the left side tables. Adjust the right side
// with the equal field if "replace" is set to true.
::ensure_multi_equality_fields_are_available(
args, /*arg_idx=*/1, left_side_tables, replace, found);
} else if (IsSubset(right_arg_used_tables, left_side_tables) &&
!IsSubset(left_arg_used_tables, right_side_tables)) {
// The right argument matches the left side tables, so find an
// "equal" field from the right side tables. Adjust the left side
// with the equal field if "replace" is set to true.
::ensure_multi_equality_fields_are_available(
args, /*arg_idx=*/0, right_side_tables, replace, found);
} else if (IsSubset(right_arg_used_tables, right_side_tables) &&
!IsSubset(left_arg_used_tables, left_side_tables)) {
// The right argument matches the right side tables, so find an
// "equal" field from the left side tables. Adjust the left side
// with the equal field if "replace" is set to true.
::ensure_multi_equality_fields_are_available(
args, /*arg_idx=*/0, left_side_tables, replace, found);
}
// We must update used_tables in case we replaced any of the fields in this
// join condition.
if (replace) update_used_tables();
}
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