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No more LateWrite, but there is WriteMode;

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SetBufferWriteMode () added;
FlushBuffer () fixed: now directly calls smgrflush () and
	releases buffer only if required by caller.
This commit is contained in:
Vadim B. Mikheev 1997-01-16 08:11:41 +00:00
parent 1c297d429e
commit eb08b3ce4f
1 changed files with 44 additions and 17 deletions
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61
src/backend/storage/buffer/bufmgr.c
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@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/storage/buffer/bufmgr.c,v 1.7 1997/01/14 05:40:45 vadim Exp $
* $Header: /cvsroot/pgsql/src/backend/storage/buffer/bufmgr.c,v 1.8 1997/01/16 08:11:41 vadim Exp $
*
*-------------------------------------------------------------------------
*/
@ -26,7 +26,7 @@
*
* WriteNoReleaseBuffer() -- mark the buffer contents as "dirty"
* but don't unpin. The disk IO is delayed until buffer
* replacement if LateWrite flag is set.
* replacement if WriteMode is BUFFER_LATE_WRITE.
*
* WriteBuffer() -- WriteNoReleaseBuffer() + ReleaseBuffer()
*
@ -74,12 +74,13 @@
#include "executor/execdebug.h" /* for NDirectFileRead */
#include "catalog/catalog.h"
extern int LateWrite;
extern SPINLOCK BufMgrLock;
extern int ReadBufferCount;
extern int BufferHitCount;
extern int BufferFlushCount;
static int WriteMode = BUFFER_LATE_WRITE; /* Delayed write is default */
static void WaitIO(BufferDesc *buf, SPINLOCK spinlock);
#ifndef HAS_TEST_AND_SET
static void SignalIO(BufferDesc *buf);
@ -90,7 +91,7 @@ static Buffer ReadBufferWithBufferLock(Relation relation, BlockNumber blockNum,
bool bufferLockHeld);
static BufferDesc *BufferAlloc(Relation reln, BlockNumber blockNum,
bool *foundPtr, bool bufferLockHeld);
static int FlushBuffer(Buffer buffer);
static int FlushBuffer (Buffer buffer, bool release);
static void BufferSync(void);
static int BufferReplace(BufferDesc *bufHdr, bool bufferLockHeld);
@ -611,8 +612,8 @@ BufferAlloc(Relation reln,
/*
* WriteBuffer--
*
* Pushes buffer contents to disk if LateWrite is
* not set. Otherwise, marks contents as dirty.
* Pushes buffer contents to disk if WriteMode is BUFFER_FLUSH_WRITE.
* Otherwise, marks contents as dirty.
*
* Assume that buffer is pinned. Assume that reln is
* valid.
@ -628,8 +629,8 @@ WriteBuffer(Buffer buffer)
{
BufferDesc *bufHdr;
if (! LateWrite) {
return(FlushBuffer(buffer));
if (WriteMode == BUFFER_FLUSH_WRITE) {
return (FlushBuffer (buffer, TRUE));
} else {
if (BufferIsLocal(buffer))
@ -712,26 +713,41 @@ DirtyBufferCopy(Oid dbid, Oid relid, BlockNumber blkno, char *dest)
* us).
*/
static int
FlushBuffer(Buffer buffer)
FlushBuffer(Buffer buffer, bool release)
{
BufferDesc *bufHdr;
Oid bufdb;
Relation bufrel;
int status;
if (BufferIsLocal(buffer))
return FlushLocalBuffer(buffer);
return FlushLocalBuffer(buffer, release);
if (BAD_BUFFER_ID(buffer))
return (STATUS_ERROR);
bufHdr = &BufferDescriptors[buffer-1];
bufdb = bufHdr->tag.relId.dbId;
if (!BufferReplace(bufHdr, false)) {
elog(WARN, "FlushBuffer: cannot flush %d", bufHdr->tag.blockNum);
Assert (bufdb == MyDatabaseId || bufdb == (Oid) NULL);
bufrel = RelationIdCacheGetRelation (bufHdr->tag.relId.relId);
Assert (bufrel != (Relation) NULL);
status = smgrflush(bufHdr->bufsmgr, bufrel, bufHdr->tag.blockNum,
(char *) MAKE_PTR(bufHdr->data));
if (status == SM_FAIL)
{
elog(WARN, "FlushBuffer: cannot flush block %u of the relation %.*s",
bufHdr->tag.blockNum,
NAMEDATALEN, bufrel->rd_rel->relname.data);
return (STATUS_ERROR);
}
SpinAcquire(BufMgrLock);
bufHdr->flags &= ~BM_DIRTY;
UnpinBuffer(bufHdr);
if ( release )
UnpinBuffer(bufHdr);
SpinRelease(BufMgrLock);
return(STATUS_OK);
@ -750,8 +766,8 @@ WriteNoReleaseBuffer(Buffer buffer)
{
BufferDesc *bufHdr;
if (! LateWrite) {
return(FlushBuffer(buffer));
if (WriteMode == BUFFER_FLUSH_WRITE) {
return (FlushBuffer (buffer, FALSE));
} else {
if (BufferIsLocal(buffer))
@ -899,7 +915,11 @@ BufferSync()
elog(WARN, "cannot write %u for %s",
bufHdr->tag.blockNum, bufHdr->sb_relname);
}
/*
* What if someone has marked this buffer as DIRTY after
* smgr[blind]write but before SpinAcquire(BufMgrLock)
* ??? - vadim 01/16/97
*/
bufHdr->flags &= ~BM_DIRTY;
if (reln != (Relation)NULL)
RelationDecrementReferenceCount(reln);
@ -1145,7 +1165,6 @@ BufferGetRelation(Buffer buffer)
*
* Flush the buffer corresponding to 'bufHdr'
*
* Assumes that the BufMgrLock has NOT been acquired.
*/
static int
BufferReplace(BufferDesc *bufHdr, bool bufferLockHeld)
@ -1655,3 +1674,11 @@ BufferRefCountRestore(int *refcountsave)
}
}
int SetBufferWriteMode (int mode)
{
int old;
old = WriteMode;
WriteMode = mode;
return (old);
}