diff options
Diffstat (limited to 'src/backend/optimizer/plan/planner.c')
| -rw-r--r-- | src/backend/optimizer/plan/planner.c | 23 |
1 files changed, 11 insertions, 12 deletions
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c index 969f3711389..5f3c7510cdd 100644 --- a/src/backend/optimizer/plan/planner.c +++ b/src/backend/optimizer/plan/planner.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/plan/planner.c,v 1.180 2005/03/17 23:44:26 neilc Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/plan/planner.c,v 1.181 2005/03/28 00:58:23 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -422,13 +422,17 @@ preprocess_expression(Query *parse, Node *expr, int kind) expr = flatten_join_alias_vars(parse, expr); /* - * If it's a qual or havingQual, canonicalize it. It seems most - * useful to do this before applying eval_const_expressions, since the - * latter can optimize flattened AND/ORs better than unflattened ones. + * Simplify constant expressions. * - * Note: all processing of a qual expression after this point must be - * careful to maintain AND/OR flatness --- that is, do not generate a - * tree with AND directly under AND, nor OR directly under OR. + * Note: this also flattens nested AND and OR expressions into N-argument + * form. All processing of a qual expression after this point must be + * careful to maintain AND/OR flatness --- that is, do not generate a tree + * with AND directly under AND, nor OR directly under OR. + */ + expr = eval_const_expressions(expr); + + /* + * If it's a qual or havingQual, canonicalize it. */ if (kind == EXPRKIND_QUAL) { @@ -440,11 +444,6 @@ preprocess_expression(Query *parse, Node *expr, int kind) #endif } - /* - * Simplify constant expressions. - */ - expr = eval_const_expressions(expr); - /* Expand SubLinks to SubPlans */ if (parse->hasSubLinks) expr = SS_process_sublinks(expr, (kind == EXPRKIND_QUAL)); |