From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Wed, 1 Jun 2011 21:01:59 +0000 (-0400)
Subject: Allow hash joins to be interrupted while searching hash table for match.
X-Git-Tag: REL9_1_BETA2~44
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=0c99d41ec887051fb0cc6e35e358ecc936a13584;p=postgresql

Allow hash joins to be interrupted while searching hash table for match.

Per experimentation with a recent example, in which unreasonable amounts
of time could elapse before the backend would respond to a query-cancel.

This might be something to back-patch, but the patch doesn't apply cleanly
because this code was rewritten for 9.1.  Given the lack of field
complaints I won't bother for now.

Cédric Villemain
---

diff --git a/src/backend/executor/nodeHashjoin.c b/src/backend/executor/nodeHashjoin.c
index 26da3b2fdf..0e7ca625ce 100644
--- a/src/backend/executor/nodeHashjoin.c
+++ b/src/backend/executor/nodeHashjoin.c
@@ -19,6 +19,7 @@
 #include "executor/hashjoin.h"
 #include "executor/nodeHash.h"
 #include "executor/nodeHashjoin.h"
+#include "miscadmin.h"
 #include "utils/memutils.h"
 
 
@@ -262,6 +263,13 @@ ExecHashJoin(HashJoinState *node)
 
 			case HJ_SCAN_BUCKET:
 
+				/*
+				 * We check for interrupts here because this corresponds to
+				 * where we'd fetch a row from a child plan node in other
+				 * join types.
+				 */
+				CHECK_FOR_INTERRUPTS();
+
 				/*
 				 * Scan the selected hash bucket for matches to current outer
 				 */