postgresql/contrib/hstore/hstore_gin.c
Tom Lane 9b5c8d45f6 Push index operator lossiness determination down to GIST/GIN opclass
"consistent" functions, and remove pg_amop.opreqcheck, as per recent
discussion.  The main immediate benefit of this is that we no longer need
8.3's ugly hack of requiring @@@ rather than @@ to test weight-using tsquery
searches on GIN indexes.  In future it should be possible to optimize some
other queries better than is done now, by detecting at runtime whether the
index match is exact or not.

Tom Lane, after an idea of Heikki's, and with some help from Teodor.
2008-04-14 17:05:34 +00:00

146 lines
3.0 KiB
C

#include "hstore.h"
#include "access/gin.h"
#define KEYFLAG 'K'
#define VALFLAG 'V'
#define NULLFLAG 'N'
PG_FUNCTION_INFO_V1(gin_extract_hstore);
Datum gin_extract_hstore(PG_FUNCTION_ARGS);
static text *
makeitem(char *str, int len)
{
text *item;
item = (text *) palloc(VARHDRSZ + len + 1);
SET_VARSIZE(item, VARHDRSZ + len + 1);
if (str && len > 0)
memcpy(VARDATA(item) + 1, str, len);
return item;
}
Datum
gin_extract_hstore(PG_FUNCTION_ARGS)
{
HStore *hs = PG_GETARG_HS(0);
int32 *nentries = (int32 *) PG_GETARG_POINTER(1);
Datum *entries = NULL;
*nentries = 2 * hs->size;
if (hs->size > 0)
{
HEntry *ptr = ARRPTR(hs);
char *words = STRPTR(hs);
int i = 0;
entries = (Datum *) palloc(sizeof(Datum) * 2 * hs->size);
while (ptr - ARRPTR(hs) < hs->size)
{
text *item;
item = makeitem(words + ptr->pos, ptr->keylen);
*VARDATA(item) = KEYFLAG;
entries[i++] = PointerGetDatum(item);
if (ptr->valisnull)
{
item = makeitem(NULL, 0);
*VARDATA(item) = NULLFLAG;
}
else
{
item = makeitem(words + ptr->pos + ptr->keylen, ptr->vallen);
*VARDATA(item) = VALFLAG;
}
entries[i++] = PointerGetDatum(item);
ptr++;
}
}
PG_FREE_IF_COPY(hs, 0);
PG_RETURN_POINTER(entries);
}
PG_FUNCTION_INFO_V1(gin_extract_hstore_query);
Datum gin_extract_hstore_query(PG_FUNCTION_ARGS);
Datum
gin_extract_hstore_query(PG_FUNCTION_ARGS)
{
StrategyNumber strategy = PG_GETARG_UINT16(2);
if (strategy == HStoreContainsStrategyNumber)
{
PG_RETURN_DATUM(DirectFunctionCall2(
gin_extract_hstore,
PG_GETARG_DATUM(0),
PG_GETARG_DATUM(1)
));
}
else if (strategy == HStoreExistsStrategyNumber)
{
text *item,
*q = PG_GETARG_TEXT_P(0);
int32 *nentries = (int32 *) PG_GETARG_POINTER(1);
Datum *entries = NULL;
*nentries = 1;
entries = (Datum *) palloc(sizeof(Datum));
item = makeitem(VARDATA(q), VARSIZE(q) - VARHDRSZ);
*VARDATA(item) = KEYFLAG;
entries[0] = PointerGetDatum(item);
PG_RETURN_POINTER(entries);
}
else
elog(ERROR, "Unsupported strategy number: %d", strategy);
PG_RETURN_POINTER(NULL);
}
PG_FUNCTION_INFO_V1(gin_consistent_hstore);
Datum gin_consistent_hstore(PG_FUNCTION_ARGS);
Datum
gin_consistent_hstore(PG_FUNCTION_ARGS)
{
bool *check = (bool *) PG_GETARG_POINTER(0);
StrategyNumber strategy = PG_GETARG_UINT16(1);
HStore *query = PG_GETARG_HS(2);
bool *recheck = (bool *) PG_GETARG_POINTER(3);
bool res = true;
if (strategy == HStoreContainsStrategyNumber)
{
int i;
/*
* Index lost information about correspondence of keys
* and values, so we need recheck
*/
*recheck = true;
for (i = 0; res && i < 2 * query->size; i++)
if (check[i] == false)
res = false;
}
else if (strategy == HStoreExistsStrategyNumber)
{
/* Existence of key is guaranteed */
*recheck = false;
res = true;
}
else
elog(ERROR, "Unsupported strategy number: %d", strategy);
PG_RETURN_BOOL(res);
}