diff options
Diffstat (limited to 'src/backend/storage/buffer/bufmgr.c')
| -rw-r--r-- | src/backend/storage/buffer/bufmgr.c | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c index 446917a4c50..e81b2dfb96b 100644 --- a/src/backend/storage/buffer/bufmgr.c +++ b/src/backend/storage/buffer/bufmgr.c @@ -7,7 +7,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/storage/buffer/bufmgr.c,v 1.55 1999/06/11 09:00:02 vadim Exp $ + * $Header: /cvsroot/pgsql/src/backend/storage/buffer/bufmgr.c,v 1.56 1999/06/29 04:54:47 vadim Exp $ * *------------------------------------------------------------------------- */ @@ -78,6 +78,15 @@ extern long int LocalBufferHitCount; extern long int BufferFlushCount; extern long int LocalBufferFlushCount; +/* + * It's used to avoid disk writes for read-only transactions + * (i.e. when no one shared buffer was changed by transaction). + * We set it to true in WriteBuffer/WriteNoReleaseBuffer when + * marking shared buffer as dirty. We set it to false in xact.c + * after transaction is committed/aborted. + */ +bool SharedBufferChanged = false; + static int WriteMode = BUFFER_LATE_WRITE; /* Delayed write is * default */ @@ -699,6 +708,8 @@ WriteBuffer(Buffer buffer) bufHdr = &BufferDescriptors[buffer - 1]; + SharedBufferChanged = true; + SpinAcquire(BufMgrLock); Assert(bufHdr->refcount > 0); bufHdr->flags |= (BM_DIRTY | BM_JUST_DIRTIED); @@ -810,6 +821,8 @@ FlushBuffer(Buffer buffer, bool release) bufrel = RelationIdCacheGetRelation(bufHdr->tag.relId.relId); Assert(bufrel != (Relation) NULL); + SharedBufferChanged = true; + /* To check if block content changed while flushing. - vadim 01/17/97 */ SpinAcquire(BufMgrLock); bufHdr->flags &= ~BM_JUST_DIRTIED; @@ -875,6 +888,8 @@ WriteNoReleaseBuffer(Buffer buffer) bufHdr = &BufferDescriptors[buffer - 1]; + SharedBufferChanged = true; + SpinAcquire(BufMgrLock); bufHdr->flags |= (BM_DIRTY | BM_JUST_DIRTIED); SpinRelease(BufMgrLock); |