From a36a20aa5223787a74d9c282362403b52dbed6be Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Wed, 24 Sep 2008 16:53:00 +0000
Subject: [PATCH] Fix more problems with rewriter failing to set
 Query.hasSubLinks when inserting a SubLink expression into a rule query.  We
 missed cases where the original query contained a sub-SELECT in a function in
 FROM, a multi-row VALUES list, or a RETURNING list.  Per bug #4434 from Dean
 Rasheed and subsequent investigation.

Back-patch to 8.1; older releases don't have the issue because they didn't
try to be smart about setting hasSubLinks only when needed.
---
 src/backend/rewrite/rewriteHandler.c | 41 +++++++++++++++++++++++++++-
 1 file changed, 40 insertions(+), 1 deletion(-)

diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index cd7f72d5756..8c5ee1bb885 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/rewrite/rewriteHandler.c,v 1.168.2.1 2007/03/01 18:50:36 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/rewrite/rewriteHandler.c,v 1.168.2.2 2008/09/24 16:53:00 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -345,6 +345,37 @@ rewriteRuleAction(Query *parsetree,
 	sub_action->rtable = list_concat((List *) copyObject(parsetree->rtable),
 									 sub_action->rtable);
 
+	/*
+	 * There could have been some SubLinks in parsetree's rtable, in which
+	 * case we'd better mark the sub_action correctly.
+	 */
+	if (parsetree->hasSubLinks && !sub_action->hasSubLinks)
+	{
+		ListCell   *lc;
+
+		foreach(lc, parsetree->rtable)
+		{
+			RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
+
+			switch (rte->rtekind)
+			{
+				case RTE_FUNCTION:
+					sub_action->hasSubLinks =
+						checkExprHasSubLink(rte->funcexpr);
+					break;
+				case RTE_VALUES:
+					sub_action->hasSubLinks =
+						checkExprHasSubLink((Node *) rte->values_lists);
+					break;
+				default:
+					/* other RTE types don't contain bare expressions */
+					break;
+			}
+			if (sub_action->hasSubLinks)
+				break;		/* no need to keep scanning rtable */
+		}
+	}
+
 	/*
 	 * Each rule action's jointree should be the main parsetree's jointree
 	 * plus that rule's jointree, but usually *without* the original rtindex
@@ -454,6 +485,14 @@ rewriteRuleAction(Query *parsetree,
 					   rule_action->returningList,
 					   CMD_SELECT,
 					   0);
+
+		/*
+		 * There could have been some SubLinks in parsetree's returningList,
+		 * in which case we'd better mark the rule_action correctly.
+		 */
+		if (parsetree->hasSubLinks && !rule_action->hasSubLinks)
+			rule_action->hasSubLinks =
+					checkExprHasSubLink((Node *) rule_action->returningList);
 	}
 
 	return rule_action;