From 37a4d3d70617f574b9a3dd5af079430b24817333 Mon Sep 17 00:00:00 2001 From: Noah Misch 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 edc603f6a1..10077483d3 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; -- 2.40.0