From 3e63e8462f31657c8ae1c541c92daf43ede8f038 Mon Sep 17 00:00:00 2001 From: Robert Haas Date: Thu, 18 Aug 2022 11:09:39 -0400 Subject: [PATCH] When using the WAL-logged CREATE DATABASE strategy, bulk extend. This should improve performance, and was suggested by Andres Freund. Back-patch to v15 to keep the code consistent across branches. Dilip Kumar Discussion: http://postgr.es/m/C3458199-FEDD-4356-865A-08DFAA5D4065@anarazel.de Discussion: http://postgr.es/m/CAFiTN-sJ0vVpJrZ=R5M+g7Tr8=NN4wKOtrqOcDEsfFfnZgivVA@mail.gmail.com --- src/backend/storage/buffer/bufmgr.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c index 9c1bd508d36..7a1202c6096 100644 --- a/src/backend/storage/buffer/bufmgr.c +++ b/src/backend/storage/buffer/bufmgr.c @@ -3712,6 +3712,7 @@ RelationCopyStorageUsingBuffer(RelFileLocator srclocator, bool use_wal; BlockNumber nblocks; BlockNumber blkno; + PGAlignedBlock buf; BufferAccessStrategy bstrategy_src; BufferAccessStrategy bstrategy_dst; @@ -3730,6 +3731,14 @@ RelationCopyStorageUsingBuffer(RelFileLocator srclocator, if (nblocks == 0) return; + /* + * Bulk extend the destination relation of the same size as the source + * relation before starting to copy block by block. + */ + memset(buf.data, 0, BLCKSZ); + smgrextend(smgropen(dstlocator, InvalidBackendId), forkNum, nblocks - 1, + buf.data, true); + /* This is a bulk operation, so use buffer access strategies. */ bstrategy_src = GetAccessStrategy(BAS_BULKREAD); bstrategy_dst = GetAccessStrategy(BAS_BULKWRITE); @@ -3747,7 +3756,7 @@ RelationCopyStorageUsingBuffer(RelFileLocator srclocator, srcPage = BufferGetPage(srcBuf); /* Use P_NEW to extend the destination relation. */ - dstBuf = ReadBufferWithoutRelcache(dstlocator, forkNum, P_NEW, + dstBuf = ReadBufferWithoutRelcache(dstlocator, forkNum, blkno, RBM_NORMAL, bstrategy_dst, permanent); LockBuffer(dstBuf, BUFFER_LOCK_EXCLUSIVE); -- 2.30.2