From dccfa4d3f2f9716632ad946a1582bff3be9e70f0 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Fri, 18 Nov 2005 23:08:13 +0000 Subject: Fix performance issue in exprTypmod(): for a COALESCE expression, it recursed twice on its first argument, leading to exponential time spent on a deep nest of COALESCEs ... such as a deeply nested FULL JOIN would produce. Per report from Matt Carter. --- src/backend/parser/parse_expr.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) (limited to 'src/backend/parser/parse_expr.c') diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c index ab9279abd30..9146887adc3 100644 --- a/src/backend/parser/parse_expr.c +++ b/src/backend/parser/parse_expr.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/parser/parse_expr.c,v 1.185 2005/10/15 02:49:22 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/parser/parse_expr.c,v 1.185.2.1 2005/11/18 23:08:13 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -1664,8 +1664,12 @@ exprTypmod(Node *expr) int32 typmod; ListCell *arg; + if (exprType((Node *) linitial(cexpr->args)) != coalescetype) + return -1; typmod = exprTypmod((Node *) linitial(cexpr->args)); - foreach(arg, cexpr->args) + if (typmod < 0) + return -1; /* no point in trying harder */ + for_each_cell(arg, lnext(list_head(cexpr->args))) { Node *e = (Node *) lfirst(arg); @@ -1688,8 +1692,12 @@ exprTypmod(Node *expr) int32 typmod; ListCell *arg; + if (exprType((Node *) linitial(mexpr->args)) != minmaxtype) + return -1; typmod = exprTypmod((Node *) linitial(mexpr->args)); - foreach(arg, mexpr->args) + if (typmod < 0) + return -1; /* no point in trying harder */ + for_each_cell(arg, lnext(list_head(mexpr->args))) { Node *e = (Node *) lfirst(arg); -- cgit v1.2.3