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MDEV-15073: Generic UDAF parser code in server for windows functions

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Added support for usual agreggate UDF (UDAF)
Added remove() call support for more efficient window function processing
Added example of aggregate UDF with efficient windows function support
This commit is contained in:
Oleksandr Byelkin 2018-11-20 10:58:34 +01:00
parent a956260d82
commit 555921a9c3
10 changed files with 386 additions and 0 deletions
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139
sql/udf_example.c
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@ -173,6 +173,13 @@ void avgcost_reset( UDF_INIT* initid, UDF_ARGS* args, char* is_null, char *error
void avgcost_clear( UDF_INIT* initid, char* is_null, char *error );
void avgcost_add( UDF_INIT* initid, UDF_ARGS* args, char* is_null, char *error );
double avgcost( UDF_INIT* initid, UDF_ARGS* args, char* is_null, char *error );
my_bool avg2_init( UDF_INIT* initid, UDF_ARGS* args, char* message );
void avg2_deinit( UDF_INIT* initid );
void avg2_reset( UDF_INIT* initid, UDF_ARGS* args, char* is_null, char *error );
void avg2_clear( UDF_INIT* initid, char* is_null, char *error );
void avg2_add( UDF_INIT* initid, UDF_ARGS* args, char* is_null, char *error );
void avg2_remove( UDF_INIT* initid, UDF_ARGS* args, char* is_null, char *error );
double avg2( UDF_INIT* initid, UDF_ARGS* args, char* is_null, char *error );
my_bool is_const_init(UDF_INIT *initid, UDF_ARGS *args, char *message);
char *is_const(UDF_INIT *initid, UDF_ARGS *args, char *result, unsigned long
*length, char *is_null, char *error);
@ -1049,6 +1056,138 @@ avgcost( UDF_INIT* initid, UDF_ARGS* args __attribute__((unused)),
return data->totalprice/(double)data->totalquantity;
}
/*
** Average 2 (number, sum)*/
struct avg2_data
{
ulonglong count;
double sum;
};
my_bool
avg2_init( UDF_INIT* initid, UDF_ARGS* args, char* message )
{
struct avg2_data* data;
if (args->arg_count != 2)
{
strcpy(
message,
"wrong number of arguments: AVG2() requires two arguments"
);
return 1;
}
if ((args->arg_type[0] != INT_RESULT) || (args->arg_type[1] != REAL_RESULT) )
{
strcpy(
message,
"wrong argument type: AVG2() requires an INT and a REAL"
);
return 1;
}
/*
** force arguments to double.
*/
/*args->arg_type[0] = REAL_RESULT;
args->arg_type[1] = REAL_RESULT;*/
initid->maybe_null = 0; /* The result may be null */
initid->decimals = 4; /* We want 4 decimals in the result */
initid->max_length = 20; /* 6 digits + . + 10 decimals */
if (!(data = (struct avg2_data*) malloc(sizeof(struct avg2_data))))
{
strmov(message,"Couldn't allocate memory");
return 1;
}
data->count = 0;
data->sum = 0.0;
initid->ptr = (char*)data;
return 0;
}
void
avg2_deinit( UDF_INIT* initid )
{
free(initid->ptr);
}
/* This is only for MySQL 4.0 compability */
void
avg2_reset(UDF_INIT* initid, UDF_ARGS* args, char* is_null, char* message)
{
avgcost_clear(initid, is_null, message);
avgcost_add(initid, args, is_null, message);
}
/* This is needed to get things to work in MySQL 4.1.1 and above */
void
avg2_clear(UDF_INIT* initid, char* is_null __attribute__((unused)),
char* message __attribute__((unused)))
{
struct avg2_data* data = (struct avg2_data*)initid->ptr;
data->sum= 0.0;
data->count= 0;
}
void
avg2_add(UDF_INIT* initid, UDF_ARGS* args,
char* is_null __attribute__((unused)),
char* message __attribute__((unused)))
{
if (args->args[0] && args->args[1])
{
struct avg2_data* data = (struct avg2_data*)initid->ptr;
longlong quantity = *((longlong*)args->args[0]);
double sum = *((double*)args->args[1]);
data->count += quantity;
data->sum += sum;
}
}
void
avg2_remove(UDF_INIT* initid, UDF_ARGS* args,
char* is_null __attribute__((unused)),
char* message __attribute__((unused)))
{
if (args->args[0] && args->args[1])
{
struct avg2_data* data = (struct avg2_data*)initid->ptr;
longlong quantity = *((longlong*)args->args[0]);
double sum = *((double*)args->args[1]);
data->count -= quantity;
data->sum -= sum;
}
}
double
avg2( UDF_INIT* initid, UDF_ARGS* args __attribute__((unused)),
char* is_null, char* error __attribute__((unused)))
{
struct avg2_data* data = (struct avg2_data*)initid->ptr;
if (!data->count)
{
*is_null = 1;
return 0.0;
}
*is_null = 0;
return data->sum/(double)data->count;
}
my_bool myfunc_argument_name_init(UDF_INIT *initid, UDF_ARGS *args,
char *message);
char *myfunc_argument_name(UDF_INIT *initid, UDF_ARGS *args, char *result,