From acd3a4f3c5cce6697f0b152438b7a25288a6aff7 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Fri, 18 Nov 2005 23:08:28 +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 | 8 ++++++-- 1 file changed, 6 insertions(+), 2 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 9082efe7eaf..f95e58593a4 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 1.179.4.2 2005/05/25 02:17:55 ishii Exp $ + * $PostgreSQL: pgsql/src/backend/parser/parse_expr.c,v 1.179.4.3 2005/11/18 23:08:28 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -1562,8 +1562,12 @@ 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); -- cgit v1.2.3