From: Heikki Linnakangas <heikki.linnakangas@iki.fi>
Date: Tue, 22 Apr 2014 12:34:54 +0000 (+0300)
Subject: Fix bug in new B-tree page deletion code.
X-Git-Tag: REL9_4_BETA1~135
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=77fe2b6d795f3f4ed282c9c980920e128a57624e;p=postgresql

Fix bug in new B-tree page deletion code.

When modifying a page, must hold an exclusive lock. A shared lock is
obviously not good enough.
---

diff --git a/src/backend/access/nbtree/nbtpage.c b/src/backend/access/nbtree/nbtpage.c
index 87ac5f4aaf..b95c1b886d 100644
--- a/src/backend/access/nbtree/nbtpage.c
+++ b/src/backend/access/nbtree/nbtpage.c
@@ -996,7 +996,7 @@ _bt_lock_branch_parent(Relation rel, BlockNumber child, BTStack stack,
 
 	/* Locate the parent's downlink (updating the stack entry if needed) */
 	ItemPointerSet(&(stack->bts_btentry.t_tid), child, P_HIKEY);
-	pbuf = _bt_getstackbuf(rel, stack, BT_READ);
+	pbuf = _bt_getstackbuf(rel, stack, BT_WRITE);
 	if (pbuf == InvalidBuffer)
 		elog(ERROR, "failed to re-find parent key in index \"%s\" for deletion target page %u",
 			 RelationGetRelationName(rel), child);