diff options
Diffstat (limited to 'src/backend/optimizer/util/restrictinfo.c')
| -rw-r--r-- | src/backend/optimizer/util/restrictinfo.c | 20 |
1 files changed, 12 insertions, 8 deletions
diff --git a/src/backend/optimizer/util/restrictinfo.c b/src/backend/optimizer/util/restrictinfo.c index deb16152fb8..47b90aef46a 100644 --- a/src/backend/optimizer/util/restrictinfo.c +++ b/src/backend/optimizer/util/restrictinfo.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/util/restrictinfo.c,v 1.39 2005/07/28 20:26:21 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/util/restrictinfo.c,v 1.40 2005/10/13 00:06:46 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -123,9 +123,13 @@ make_restrictinfo_from_bitmapqual(Path *bitmapqual, List *withoutris = NIL; /* - * Here, we detect both obvious redundancies and qual-free subplans. - * A qual-free subplan would cause us to generate "... OR true ..." - * which we may as well reduce to just "true". + * Here, we only detect qual-free subplans. A qual-free subplan would + * cause us to generate "... OR true ..." which we may as well reduce + * to just "true". We do not try to eliminate redundant subclauses + * because (a) it's not as likely as in the AND case, and (b) we might + * well be working with hundreds or even thousands of OR conditions, + * perhaps from a long IN list. The performance of list_append_unique + * would be unacceptable. */ foreach(l, opath->bitmapquals) { @@ -144,12 +148,12 @@ make_restrictinfo_from_bitmapqual(Path *bitmapqual, return NIL; } /* Create AND subclause with RestrictInfos */ - withris = list_append_unique(withris, - make_ands_explicit(sublist)); + withris = lappend(withris, + make_ands_explicit(sublist)); /* And one without */ sublist = get_actual_clauses(sublist); - withoutris = list_append_unique(withoutris, - make_ands_explicit(sublist)); + withoutris = lappend(withoutris, + make_ands_explicit(sublist)); } /* |