From 2146f13408cdb85c738364fe8f7965209e08c6be Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Mon, 16 Jun 2014 15:55:05 -0400 Subject: Avoid recursion when processing simple lists of AND'ed or OR'ed clauses. Since most of the system thinks AND and OR are N-argument expressions anyway, let's have the grammar generate a representation of that form when dealing with input like "x AND y AND z AND ...", rather than generating a deeply-nested binary tree that just has to be flattened later by the planner. This avoids stack overflow in parse analysis when dealing with queries having more than a few thousand such clauses; and in any case it removes some rather unsightly inconsistencies, since some parts of parse analysis were generating N-argument ANDs/ORs already. It's still possible to get a stack overflow with weirdly parenthesized input, such as "x AND (y AND (z AND ( ... )))", but such cases are not mainstream usage. The maximum depth of parenthesization is already limited by Bison's stack in such cases, anyway, so that the limit is probably fairly platform-independent. Patch originally by Gurjeet Singh, heavily revised by me --- contrib/postgres_fdw/deparse.c | 3 --- 1 file changed, 3 deletions(-) (limited to 'contrib/postgres_fdw/deparse.c') diff --git a/contrib/postgres_fdw/deparse.c b/contrib/postgres_fdw/deparse.c index d7d9b9c77d2..322138dd0cd 100644 --- a/contrib/postgres_fdw/deparse.c +++ b/contrib/postgres_fdw/deparse.c @@ -1716,9 +1716,6 @@ deparseRelabelType(RelabelType *node, deparse_expr_cxt *context) /* * Deparse a BoolExpr node. - * - * Note: by the time we get here, AND and OR expressions have been flattened - * into N-argument form, so we'd better be prepared to deal with that. */ static void deparseBoolExpr(BoolExpr *node, deparse_expr_cxt *context) -- cgit v1.2.3