postgres.git / summary / log / commit / refs
commit 5df319f3d55d09fadb4f7e4b58c5b476a3aeceb4
Author: Andres Freund <andres@anarazel.de>
Date: Tue Mar 21 04:57:40 2023 +0000
First released in: 16.0, 15.3
Fix memory leak and inefficiency in CREATE DATABASE ... STRATEGY WAL_LOG
RelationCopyStorageUsingBuffer() did not free the strategies used to access
the source / target relation. They memory was released at the end of the
transaction, but when using a template database with a lot of relations, the
temporary leak can become big prohibitively big.
RelationCopyStorageUsingBuffer() acquired the buffer for the target relation
with RBM_NORMAL, therefore requiring a read of a block guaranteed to be
zero. Use RBM_ZERO_AND_LOCK instead.
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Discussion: https://postgr.es/m/20230321070113.o2vqqxogjykwgfrr@awork3.anarazel.de
Backpatch: 15-, where STRATEGY WAL_LOG was introduced
src/backend/storage/buffer/bufmgr.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 0a05577b68d..95212a39416 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -3833,11 +3833,9 @@ RelationCopyStorageUsingBuffer(RelFileLocator srclocator,
LockBuffer(srcBuf, BUFFER_LOCK_SHARE);
srcPage = BufferGetPage(srcBuf);
- /* Use P_NEW to extend the destination relation. */
dstBuf = ReadBufferWithoutRelcache(dstlocator, forkNum, blkno,
- RBM_NORMAL, bstrategy_dst,
+ RBM_ZERO_AND_LOCK, bstrategy_dst,
permanent);
- LockBuffer(dstBuf, BUFFER_LOCK_EXCLUSIVE);
dstPage = BufferGetPage(dstBuf);
START_CRIT_SECTION();
@@ -3855,6 +3853,9 @@ RelationCopyStorageUsingBuffer(RelFileLocator srclocator,
UnlockReleaseBuffer(dstBuf);
UnlockReleaseBuffer(srcBuf);
}
+
+ FreeAccessStrategy(bstrategy_src);
+ FreeAccessStrategy(bstrategy_dst);
}
/* ---------------------------------------------------------------------
[parent: bbc1376b3962]