postgres.git / summary / log / commit / refs

commit    93cd7684ee2bba227fa371daa81b88f25456dcb2
Author:   Robert Haas <rhaas@postgresql.org>
Date:     Tue Apr 04 02:24:17 2017 +0000

    Properly acquire buffer lock for page-at-a-time hash vacuum.
    
    In a couple of places, _hash_kill_items was mistakenly called with
    the buffer lock not held.  Repair.
    
    Ashutosh Sharma, per a report from Andreas Seltenreich
    
    Discussion: http://postgr.es/m/87o9wo8o0j.fsf@credativ.de


 src/backend/access/hash/hash.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/src/backend/access/hash/hash.c b/src/backend/access/hash/hash.c
index 34cc08f12d2..b835f772d46 100644
--- a/src/backend/access/hash/hash.c
+++ b/src/backend/access/hash/hash.c
@@ -476,9 +476,17 @@ hashrescan(IndexScanDesc scan, ScanKey scankey, int nscankeys,
 	HashScanOpaque so = (HashScanOpaque) scan->opaque;
 	Relation	rel = scan->indexRelation;
 
-	/* Before leaving current page, deal with any killed items */
+	/*
+	 * Before leaving current page, deal with any killed items.
+	 * Also, ensure that we acquire lock on current page before
+	 * calling _hash_kill_items.
+	 */
 	if (so->numKilled > 0)
+	{
+		LockBuffer(so->hashso_curbuf, BUFFER_LOCK_SHARE);
 		_hash_kill_items(scan);
+		LockBuffer(so->hashso_curbuf, BUFFER_LOCK_UNLOCK);
+	}
 
 	_hash_dropscanbuf(rel, so);
 
@@ -507,9 +515,17 @@ hashendscan(IndexScanDesc scan)
 	HashScanOpaque so = (HashScanOpaque) scan->opaque;
 	Relation	rel = scan->indexRelation;
 
-	/* Before leaving current page, deal with any killed items */
+	/*
+	 * Before leaving current page, deal with any killed items.
+	 * Also, ensure that we acquire lock on current page before
+	 * calling _hash_kill_items.
+	 */
 	if (so->numKilled > 0)
+	{
+		LockBuffer(so->hashso_curbuf, BUFFER_LOCK_SHARE);
 		_hash_kill_items(scan);
+		LockBuffer(so->hashso_curbuf, BUFFER_LOCK_UNLOCK);
+	}
 
 	_hash_dropscanbuf(rel, so);
 


[parent: f5780935266b]