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| author | Teodor Sigaev <teodor@sigaev.ru> | 2007-01-31 15:09:45 +0000 |
|---|---|---|
| committer | Teodor Sigaev <teodor@sigaev.ru> | 2007-01-31 15:09:45 +0000 |
| commit | d4c6da152782b580b24cd8b4054eb1b7fb72c5a0 (patch) | |
| tree | 23db426588b5ff2a39981393a3cc4b48397b4294 /contrib/intarray | |
| parent | 147a3ce149088c913b152e7d37bb92f61bb068dd (diff) | |
| download | postgresql-d4c6da152782b580b24cd8b4054eb1b7fb72c5a0.tar.gz | |
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.
Diffstat (limited to 'contrib/intarray')
| -rw-r--r-- | contrib/intarray/_int_gin.c | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/contrib/intarray/_int_gin.c b/contrib/intarray/_int_gin.c index 7bb9599b33..2248428786 100644 --- a/contrib/intarray/_int_gin.c +++ b/contrib/intarray/_int_gin.c @@ -6,7 +6,7 @@ Datum ginint4_queryextract(PG_FUNCTION_ARGS); Datum ginint4_queryextract(PG_FUNCTION_ARGS) { - uint32 *nentries = (uint32 *) PG_GETARG_POINTER(1); + int32 *nentries = (int32 *) PG_GETARG_POINTER(1); StrategyNumber strategy = PG_GETARG_UINT16(2); Datum *res = NULL; @@ -57,6 +57,19 @@ ginint4_queryextract(PG_FUNCTION_ARGS) } } + 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); } |