From 9d0826c595e2a376f6645eb575a9d81d5f5ececf Mon Sep 17 00:00:00 2001
From: Noah Misch <noah@leadboat.com>
Date: Mon, 30 Jun 2014 16:59:19 -0400
Subject: [PATCH] Don't prematurely free the BufferAccessStrategy in
pgstat_heap().
This function continued to use it after heap_endscan() freed it. In
passing, don't explicit create a strategy here. Instead, use the one
created by heap_beginscan_strat(), if any. Back-patch to 9.2, where use
of a BufferAccessStrategy here was introduced.
---
contrib/pgstattuple/pgstattuple.c | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)
diff --git a/contrib/pgstattuple/pgstattuple.c b/contrib/pgstattuple/pgstattuple.c
index edc603f6a1b..10077483d35 100644
--- a/contrib/pgstattuple/pgstattuple.c
+++ b/contrib/pgstattuple/pgstattuple.c
@@ -274,7 +274,6 @@ pgstat_heap(Relation rel, FunctionCallInfo fcinfo)
BlockNumber tupblock;
Buffer buffer;
pgstattuple_type stat = {0};
- BufferAccessStrategy bstrategy;
SnapshotData SnapshotDirty;
/* Disable syncscan because we assume we scan from block zero upwards */
@@ -283,10 +282,6 @@ pgstat_heap(Relation rel, FunctionCallInfo fcinfo)
nblocks = scan->rs_nblocks; /* # blocks to be scanned */
- /* prepare access strategy for this table */
- bstrategy = GetAccessStrategy(BAS_BULKREAD);
- scan->rs_strategy = bstrategy;
-
/* scan the relation */
while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
{
@@ -320,26 +315,28 @@ pgstat_heap(Relation rel, FunctionCallInfo fcinfo)
{
CHECK_FOR_INTERRUPTS();
- buffer = ReadBufferExtended(rel, MAIN_FORKNUM, block, RBM_NORMAL, bstrategy);
+ buffer = ReadBufferExtended(rel, MAIN_FORKNUM, block,
+ RBM_NORMAL, scan->rs_strategy);
LockBuffer(buffer, BUFFER_LOCK_SHARE);
stat.free_space += PageGetHeapFreeSpace((Page) BufferGetPage(buffer));
UnlockReleaseBuffer(buffer);
block++;
}
}
- heap_endscan(scan);
while (block < nblocks)
{
CHECK_FOR_INTERRUPTS();
- buffer = ReadBufferExtended(rel, MAIN_FORKNUM, block, RBM_NORMAL, bstrategy);
+ buffer = ReadBufferExtended(rel, MAIN_FORKNUM, block,
+ RBM_NORMAL, scan->rs_strategy);
LockBuffer(buffer, BUFFER_LOCK_SHARE);
stat.free_space += PageGetHeapFreeSpace((Page) BufferGetPage(buffer));
UnlockReleaseBuffer(buffer);
block++;
}
+ heap_endscan(scan);
relation_close(rel, AccessShareLock);
stat.table_len = (uint64) nblocks *BLCKSZ;
--
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