mysql-server/storage/innobase/ddl/ddl0buffer.cc
2025-03-05 14:31:37 +07:00

255 lines
7.6 KiB
C++

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/** @file ddl/ddl0buffer.cc
DDL key buffer implementation.
Created 2020-11-01 by Sunny Bains. */
#include "ddl0impl-buffer.h"
#include "ddl0impl-compare.h"
namespace ddl {
/** Merge sort a given array.
@param[in, out] arr Array to sort.
@param[in, out] aux_arr Auxiliary space to use for sort.
@param[in] low First element (inclusive).
@param[in] high Number of elements to sort from low.
@param[in] compare Function to compare two elements. */
template <typename T, typename Compare>
inline void merge_sort(T *arr, T *aux_arr, const size_t low, const size_t high,
Compare compare) {
ut_a(low < high);
if (low == high - 2) {
if (compare(arr[low], arr[high - 1]) > 0) {
aux_arr[low] = arr[low];
arr[low] = arr[high - 1];
arr[high - 1] = aux_arr[low];
}
return;
} else if (unlikely(low == high - 1)) {
return;
}
auto l = low;
auto h = (low + high) >> 1;
const auto m = h;
merge_sort(arr, aux_arr, low, m, compare);
merge_sort(arr, aux_arr, m, high, compare);
for (auto i = low; i < high; ++i) {
if (l >= m) {
aux_arr[i] = arr[h++];
} else if (h >= high) {
aux_arr[i] = arr[l++];
} else if (compare(arr[l], arr[h]) > 0) {
aux_arr[i] = arr[h++];
} else {
aux_arr[i] = arr[l++];
}
}
memcpy(arr + low, aux_arr + low, (high - low) * sizeof(*arr));
}
Key_sort_buffer::Key_sort_buffer(dict_index_t *index, size_t size) noexcept
: m_index(index), m_buffer_size(size) {
m_max_tuples = m_buffer_size / std::max(ulint{1}, m_index->get_min_size());
m_dtuples.resize(m_max_tuples);
m_heap = mem_heap_create(1024, UT_LOCATION_HERE);
}
void Key_sort_buffer::deep_copy(size_t n_fields, size_t data_size) noexcept {
auto field = m_dtuples[m_n_tuples++];
do {
dfield_dup(field++, m_heap);
} while (--n_fields > 0);
m_total_size += data_size;
}
void Key_sort_buffer::clear() noexcept {
m_n_tuples = 0;
m_total_size = 0;
mem_heap_empty(m_heap);
}
void Key_sort_buffer::sort(Dup *dup) noexcept {
ut_ad(!dict_index_is_spatial(m_index));
DTuples aux{};
aux.resize(m_n_tuples);
/* Compare all the columns of the key to preserve order in the index. */
Compare_key compare_key(m_index, dup, true);
merge_sort(&m_dtuples[0], &aux[0], 0, m_n_tuples, compare_key);
}
dberr_t Key_sort_buffer::serialize(IO_buffer io_buffer,
Function persist) noexcept {
std::pair<const byte *, const byte *> bounds{
io_buffer.first, io_buffer.first + io_buffer.second};
/* Points past the filled part of buffer */
auto ptr = io_buffer.first;
/* Move as many blocks as possible out of the buffer by persisting them */
auto write_buffer = [io_buffer, &ptr, persist]() -> dberr_t {
auto persist_buffer = io_buffer;
const size_t buf_filled = ptr - io_buffer.first;
persist_buffer.second = ut_uint64_align_down(buf_filled, IO_BLOCK_SIZE);
auto err = persist(persist_buffer);
if (err != DB_SUCCESS) {
return err;
}
const os_offset_t bytes_written = persist_buffer.second;
const auto bytes_remaining = buf_filled - bytes_written;
ptr = io_buffer.first;
memmove(ptr, ptr + bytes_written, bytes_remaining);
ptr += bytes_remaining;
/* Remaining contents of buffer must be less than the needed alignment.*/
ut_ad(bytes_remaining < IO_BLOCK_SIZE);
return DB_SUCCESS;
};
size_t i{};
const auto n_fields = dict_index_get_n_fields(m_index);
for (const auto &fields : m_dtuples) {
if (i++ >= m_n_tuples) {
break;
}
ulint extra_size;
const auto size = rec_get_serialize_size(m_index, fields, n_fields, nullptr,
&extra_size, MAX_ROW_VERSION);
{
const auto rec_size = size + extra_size + 2;
if (rec_size >= io_buffer.second) {
/* Single row doesn't fit into our IO buffer. */
return DB_TOO_BIG_RECORD;
}
ut_a(size >= extra_size);
}
size_t need;
char prefix[sizeof(uint16_t)];
/* Encode extra_size + 1 */
if (extra_size + 1 < 0x80) {
need = 1;
prefix[0] = (byte)(extra_size + 1);
} else {
need = 2;
ut_a((extra_size + 1) < 0x8000);
prefix[0] = (byte)(0x80 | ((extra_size + 1) >> 8));
prefix[1] = (byte)(extra_size + 1);
}
const auto rec_size = need + size;
/* If serialized record won't fit in buffer, make space in the buffer
by persisting a portion of it */
if (unlikely(ptr + rec_size > bounds.second)) {
const auto err = write_buffer();
if (err != DB_SUCCESS) {
return err;
}
ut_a(ptr + rec_size <= bounds.second);
}
memcpy(ptr, prefix, need);
ptr += need;
{
const auto p = ptr + extra_size;
rec_serialize_dtuple(p, m_index, fields, n_fields, nullptr,
MAX_ROW_VERSION);
}
ptr += size;
}
ut_a(ptr <= bounds.second);
/* At this point there is some data remaining in buffer. It needs
to be persisted, followed by zero-filled region at least 1 byte in
length and aligned to IO_BLOCK_SIZE ("end-of-chunk" marker) */
size_t buf_filled = ptr - io_buffer.first;
size_t aligned_size = ut_uint64_align_up(buf_filled + 1, IO_BLOCK_SIZE);
/* Check if adding the end-of-chunk marker would overflow the buffer */
if (aligned_size > io_buffer.second) {
/* If so, persist a portion of the buffer to free it up */
const auto err = write_buffer();
if (err != DB_SUCCESS) {
return err;
}
ut_ad(ptr >= io_buffer.first);
ut_a(size_t(ptr - io_buffer.first) < IO_BLOCK_SIZE);
/* After writing buffer contains [0, IO_BLOCK_SIZE) bytes,
so aligning it to IO_BLOCK_SIZE guarantees space for
end-of-chunk marker */
aligned_size = IO_BLOCK_SIZE;
}
/* Append the end-of-chunk marker. */
ut_a(ptr < bounds.second);
auto pad_end = io_buffer.first + aligned_size;
ut_ad(pad_end > ptr);
size_t pad_length = pad_end - ptr;
memset(ptr, 0, pad_length);
return persist({io_buffer.first, aligned_size});
}
int Key_sort_buffer::compare(const dfield_t *lhs, const dfield_t *rhs,
Dup *dup) noexcept {
ut_ad(dup->m_index->is_clustered());
Compare_key compare_key(dup->m_index, dup, false);
return compare_key(lhs, rhs);
}
} // namespace ddl