mirrors/postgres
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Avoid XLogFlush for clean buffers in BufferSync.

Browse Source
This commit is contained in:
Vadim B. Mikheev 2000-12-22 20:04:43 +00:00
parent 387d43113c
commit 369aace5f3
1 changed files with 21 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
src/backend/storage/buffer/bufmgr.c
View File

@ -8,7 +8,7 @@
* *
* *
* IDENTIFICATION * IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/storage/buffer/bufmgr.c,v 1.98 2000/11/30 19:03:25 vadim Exp $ * $Header: /cvsroot/pgsql/src/backend/storage/buffer/bufmgr.c,v 1.99 2000/12/22 20:04:43 vadim Exp $
* *
*------------------------------------------------------------------------- *-------------------------------------------------------------------------
*/ */
@ -723,6 +723,7 @@ BufferSync()
RelFileNode rnode; RelFileNode rnode;
XLogRecPtr recptr; XLogRecPtr recptr;
Relation reln = NULL; Relation reln = NULL;
bool dirty = false;
for (i = 0, bufHdr = BufferDescriptors; i < NBuffers; i++, bufHdr++) for (i = 0, bufHdr = BufferDescriptors; i < NBuffers; i++, bufHdr++)
{ {
@ -745,6 +746,7 @@ BufferSync()
buffer = BufferDescriptorGetBuffer(bufHdr); buffer = BufferDescriptorGetBuffer(bufHdr);
rnode = bufHdr->tag.rnode; rnode = bufHdr->tag.rnode;
dirty = bufHdr->flags & BM_DIRTY;
SpinRelease(BufMgrLock); SpinRelease(BufMgrLock);
@ -758,6 +760,17 @@ BufferSync()
*/ */
LockBuffer(buffer, BUFFER_LOCK_SHARE); LockBuffer(buffer, BUFFER_LOCK_SHARE);
if (!dirty && !(bufHdr->cntxDirty))
{
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
SpinAcquire(BufMgrLock);
UnpinBuffer(bufHdr);
SpinRelease(BufMgrLock);
if (reln != (Relation) NULL)
RelationDecrementReferenceCount(reln);
continue;
}
/* /*
* Force XLOG flush for buffer' LSN * Force XLOG flush for buffer' LSN
*/ */
@ -766,9 +779,8 @@ BufferSync()
/* /*
* Now it's safe to write buffer to disk * Now it's safe to write buffer to disk
* (if needed at all -:)) * (if no one else already)
*/ */
SpinAcquire(BufMgrLock); SpinAcquire(BufMgrLock);
if (bufHdr->flags & BM_IO_IN_PROGRESS) if (bufHdr->flags & BM_IO_IN_PROGRESS)
WaitIO(bufHdr, BufMgrLock); WaitIO(bufHdr, BufMgrLock);
@ -824,20 +836,19 @@ BufferSync()
*/ */
if (!(bufHdr->flags & BM_JUST_DIRTIED)) if (!(bufHdr->flags & BM_JUST_DIRTIED))
bufHdr->flags &= ~BM_DIRTY; bufHdr->flags &= ~BM_DIRTY;
UnpinBuffer(bufHdr);
SpinRelease(BufMgrLock);
} }
else else
{
UnpinBuffer(bufHdr);
SpinRelease(BufMgrLock);
LockBuffer(buffer, BUFFER_LOCK_UNLOCK); LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
}
UnpinBuffer(bufHdr);
SpinRelease(BufMgrLock);
/* drop refcnt obtained by RelationNodeCacheGetRelation */ /* drop refcnt obtained by RelationNodeCacheGetRelation */
if (reln != (Relation) NULL) if (reln != (Relation) NULL)
{
RelationDecrementReferenceCount(reln); RelationDecrementReferenceCount(reln);
reln = NULL;
}
} }
} }