Avoid disk writes for read-only transactions.
This commit is contained in:
Vadim B. Mikheev
parent
cffd0f9c89
commit
49f68a8584
|
|
@ -7,7 +7,7 @@
|
|||
*
|
||||
*
|
||||
* IDENTIFICATION
|
||||
* $Header: /cvsroot/pgsql/src/backend/access/transam/xact.c,v 1.41 1999/06/10 14:17:06 vadim Exp $
|
||||
* $Header: /cvsroot/pgsql/src/backend/access/transam/xact.c,v 1.42 1999/06/29 04:54:46 vadim Exp $
|
||||
*
|
||||
* NOTES
|
||||
* Transaction aborts can now occur two ways:
|
||||
|
|
@ -158,6 +158,8 @@
|
|||
#include <commands/sequence.h>
|
||||
#include <libpq/be-fsstubs.h>
|
||||
|
||||
extern bool SharedBufferChanged;
|
||||
|
||||
static void AbortTransaction(void);
|
||||
static void AtAbort_Cache(void);
|
||||
static void AtAbort_Locks(void);
|
||||
|
|
@ -618,30 +620,36 @@ RecordTransactionCommit()
|
|||
*/
|
||||
xid = GetCurrentTransactionId();
|
||||
|
||||
/* ----------------
|
||||
/*
|
||||
* flush the buffer manager pages. Note: if we have stable
|
||||
* main memory, dirty shared buffers are not flushed
|
||||
* plai 8/7/90
|
||||
* ----------------
|
||||
*/
|
||||
leak = BufferPoolCheckLeak();
|
||||
FlushBufferPool(!TransactionFlushEnabled());
|
||||
if (leak)
|
||||
ResetBufferPool();
|
||||
|
||||
/* ----------------
|
||||
* have the transaction access methods record the status
|
||||
* of this transaction id in the pg_log / pg_time relations.
|
||||
* ----------------
|
||||
/*
|
||||
* If no one shared buffer was changed by this transaction then
|
||||
* we don't flush shared buffers and don't record commit status.
|
||||
*/
|
||||
TransactionIdCommit(xid);
|
||||
if (SharedBufferChanged)
|
||||
{
|
||||
FlushBufferPool(!TransactionFlushEnabled());
|
||||
if (leak)
|
||||
ResetBufferPool();
|
||||
|
||||
/*
|
||||
* have the transaction access methods record the status
|
||||
* of this transaction id in the pg_log relation.
|
||||
*/
|
||||
TransactionIdCommit(xid);
|
||||
|
||||
/*
|
||||
* Now write the log info to the disk too.
|
||||
*/
|
||||
leak = BufferPoolCheckLeak();
|
||||
FlushBufferPool(!TransactionFlushEnabled());
|
||||
}
|
||||
|
||||
/* ----------------
|
||||
* Now write the log/time info to the disk too.
|
||||
* ----------------
|
||||
*/
|
||||
leak = BufferPoolCheckLeak();
|
||||
FlushBufferPool(!TransactionFlushEnabled());
|
||||
if (leak)
|
||||
ResetBufferPool();
|
||||
}
|
||||
|
|
@ -731,19 +739,14 @@ RecordTransactionAbort()
|
|||
*/
|
||||
xid = GetCurrentTransactionId();
|
||||
|
||||
/* ----------------
|
||||
* have the transaction access methods record the status
|
||||
* of this transaction id in the pg_log / pg_time relations.
|
||||
* ----------------
|
||||
/*
|
||||
* Have the transaction access methods record the status of
|
||||
* this transaction id in the pg_log relation. We skip it
|
||||
* if no one shared buffer was changed by this transaction.
|
||||
*/
|
||||
TransactionIdAbort(xid);
|
||||
if (SharedBufferChanged)
|
||||
TransactionIdAbort(xid);
|
||||
|
||||
/* ----------------
|
||||
* flush the buffer manager pages. Note: if we have stable
|
||||
* main memory, dirty shared buffers are not flushed
|
||||
* plai 8/7/90
|
||||
* ----------------
|
||||
*/
|
||||
ResetBufferPool();
|
||||
}
|
||||
|
||||
|
|
@ -965,6 +968,7 @@ CommitTransaction()
|
|||
* ----------------
|
||||
*/
|
||||
s->state = TRANS_DEFAULT;
|
||||
SharedBufferChanged = false; /* safest place to do it */
|
||||
|
||||
}
|
||||
|
||||
|
|
@ -1028,6 +1032,7 @@ AbortTransaction()
|
|||
* ----------------
|
||||
*/
|
||||
s->state = TRANS_DEFAULT;
|
||||
SharedBufferChanged = false; /* safest place to do it */
|
||||
}
|
||||
|
||||
/* --------------------------------
|
||||
|
|
|
|||
|
|
@ -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);
|
||||
|
|
|
|||
Loading…
Reference in New Issue