postgresql/contrib/intarray/_int_gin.c
Teodor Sigaev d4c6da1527 Allow GIN's extractQuery method to signal that nothing can satisfy the query.
In this case extractQuery should returns -1 as nentries. This changes
prototype of extractQuery method to use int32* instead of uint32* for
nentries argument.
Based on that gincostestimate may see two corner cases: nothing will be found
or seqscan should be used.

Per proposal at http://archives.postgresql.org/pgsql-hackers/2007-01/msg01581.php

PS tsearch_core patch should be sightly modified to support changes, but I'm
waiting a verdict about reviewing of tsearch_core patch.
2007-01-31 15:09:45 +00:00

132 lines
2.7 KiB
C

#include "_int.h"
PG_FUNCTION_INFO_V1(ginint4_queryextract);
Datum ginint4_queryextract(PG_FUNCTION_ARGS);
Datum
ginint4_queryextract(PG_FUNCTION_ARGS)
{
int32 *nentries = (int32 *) PG_GETARG_POINTER(1);
StrategyNumber strategy = PG_GETARG_UINT16(2);
Datum *res = NULL;
*nentries = 0;
if (strategy == BooleanSearchStrategy)
{
QUERYTYPE *query = (QUERYTYPE *) PG_DETOAST_DATUM_COPY(PG_GETARG_POINTER(0));
ITEM *items = GETQUERY(query);
int i;
if (query->size == 0)
PG_RETURN_POINTER(NULL);
if (shorterquery(items, query->size) == 0)
elog(ERROR, "Query requires full scan, GIN doesn't support it");
pfree(query);
query = (QUERYTYPE *) PG_DETOAST_DATUM(PG_GETARG_POINTER(0));
items = GETQUERY(query);
res = (Datum *) palloc(sizeof(Datum) * query->size);
*nentries = 0;
for (i = 0; i < query->size; i++)
if (items[i].type == VAL)
{
res[*nentries] = Int32GetDatum(items[i].val);
(*nentries)++;
}
}
else
{
ArrayType *query = PG_GETARG_ARRAYTYPE_P(0);
int4 *arr;
uint32 i;
CHECKARRVALID(query);
*nentries = ARRNELEMS(query);
if (*nentries > 0)
{
res = (Datum *) palloc(sizeof(Datum) * (*nentries));
arr = ARRPTR(query);
for (i = 0; i < *nentries; i++)
res[i] = Int32GetDatum(arr[i]);
}
}
if ( nentries == 0 )
{
switch( strategy )
{
case BooleanSearchStrategy:
case RTOverlapStrategyNumber:
*nentries = -1; /* nobody can be found */
break;
default: /* require fullscan: GIN can't find void arrays */
break;
}
}
PG_RETURN_POINTER(res);
}
PG_FUNCTION_INFO_V1(ginint4_consistent);
Datum ginint4_consistent(PG_FUNCTION_ARGS);
Datum
ginint4_consistent(PG_FUNCTION_ARGS)
{
bool *check = (bool *) PG_GETARG_POINTER(0);
StrategyNumber strategy = PG_GETARG_UINT16(1);
int res = FALSE;
/*
* we can do not check array carefully, it's done by previous
* ginarrayextract call
*/
switch (strategy)
{
case RTOverlapStrategyNumber:
case RTContainedByStrategyNumber:
case RTOldContainedByStrategyNumber:
/* at least one element in check[] is true, so result = true */
res = TRUE;
break;
case RTSameStrategyNumber:
case RTContainsStrategyNumber:
case RTOldContainsStrategyNumber:
res = TRUE;
do
{
ArrayType *query = PG_GETARG_ARRAYTYPE_P(2);
int i,
nentries = ARRNELEMS(query);
for (i = 0; i < nentries; i++)
if (!check[i])
{
res = FALSE;
break;
}
} while (0);
break;
case BooleanSearchStrategy:
do
{
QUERYTYPE *query = (QUERYTYPE *) PG_DETOAST_DATUM(PG_GETARG_POINTER(2));
res = ginconsistent(query, check);
} while (0);
break;
default:
elog(ERROR, "ginint4_consistent: unknown strategy number: %d", strategy);
}
PG_RETURN_BOOL(res);
}