diff options
| 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 /src/backend/access/gin/ginarrayproc.c | |
| parent | 147a3ce149088c913b152e7d37bb92f61bb068dd (diff) | |
| download | postgresql-d4c6da152782b580b24cd8b4054eb1b7fb72c5a0.tar.gz postgresql-d4c6da152782b580b24cd8b4054eb1b7fb72c5a0.zip | |
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 'src/backend/access/gin/ginarrayproc.c')
| -rw-r--r-- | src/backend/access/gin/ginarrayproc.c | 19 |
1 files changed, 17 insertions, 2 deletions
diff --git a/src/backend/access/gin/ginarrayproc.c b/src/backend/access/gin/ginarrayproc.c index fd505333bc5..a46def63c50 100644 --- a/src/backend/access/gin/ginarrayproc.c +++ b/src/backend/access/gin/ginarrayproc.c @@ -8,7 +8,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/access/gin/ginarrayproc.c,v 1.8 2007/01/05 22:19:21 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/access/gin/ginarrayproc.c,v 1.9 2007/01/31 15:09:45 teodor Exp $ *------------------------------------------------------------------------- */ #include "postgres.h" @@ -38,7 +38,7 @@ Datum ginarrayextract(PG_FUNCTION_ARGS) { ArrayType *array; - uint32 *nentries = (uint32 *) PG_GETARG_POINTER(1); + int32 *nentries = (int32 *) PG_GETARG_POINTER(1); Datum *entries = NULL; int16 elmlen; bool elmbyval; @@ -60,6 +60,21 @@ ginarrayextract(PG_FUNCTION_ARGS) elmlen, elmbyval, elmalign, &entries, NULL, (int *) nentries); + if ( *nentries == 0 && PG_NARGS() == 3 ) + { + switch( PG_GETARG_UINT16(2) ) + { + case GinOverlapStrategy: + *nentries = -1; /* nobody can be found */ + break; + case GinContainsStrategy: + case GinContainedStrategy: + case GinEqualStrategy: + default: /* require fullscan: GIN can't find void arrays */ + break; + } + } + /* we should not free array, entries[i] points into it */ PG_RETURN_POINTER(entries); } |