From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 12 Oct 2006 17:02:28 +0000 (+0000)
Subject: Fix mishandling of after-trigger state when a SQL function returns multiple
X-Git-Url: http://git.postgresql.org/gitweb/static/gitweb.js?a=commitdiff_plain;h=ba9b766b986c46daa209131a0dc350f3351f5233;p=users%2Fbernd%2Fpostgres.git

Fix mishandling of after-trigger state when a SQL function returns multiple
rows --- if the surrounding query queued any trigger events between the rows,
the events would be fired at the wrong time, leading to bizarre behavior.
Per report from Merlin Moncure.

This is a simple patch that should solve the problem fully in the back
branches, but in HEAD we also need to consider the possibility of queries
with RETURNING clauses.  Will look into a fix for that separately.
---

diff --git a/src/backend/executor/functions.c b/src/backend/executor/functions.c
index f3acc0a306..f18cb11430 100644
--- a/src/backend/executor/functions.c
+++ b/src/backend/executor/functions.c
@@ -329,7 +329,14 @@ postquel_start(execution_state *es, SQLFunctionCachePtr fcache)
 	/* Utility commands don't need Executor. */
 	if (es->qd->operation != CMD_UTILITY)
 	{
-		AfterTriggerBeginQuery();
+		/*
+		 * Only set up to collect queued triggers if it's not a SELECT.
+		 * This isn't just an optimization, but is necessary in case a SELECT
+		 * returns multiple rows to caller --- we mustn't exit from the
+		 * function execution with a stacked AfterTrigger level still active.
+		 */
+		if (es->qd->operation != CMD_SELECT)
+			AfterTriggerBeginQuery();
 		ExecutorStart(es->qd, false);
 	}
 
@@ -401,7 +408,8 @@ postquel_end(execution_state *es)
 		{
 			ActiveSnapshot = es->qd->snapshot;
 
-			AfterTriggerEndQuery(es->qd->estate);
+			if (es->qd->operation != CMD_SELECT)
+				AfterTriggerEndQuery(es->qd->estate);
 			ExecutorEnd(es->qd);
 		}
 		PG_CATCH();