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Avoid disk writes for read-only transactions.

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This commit is contained in:
Vadim B. Mikheev
1999-06-29 04:54:49 +00:00
parent cffd0f9c89
commit 49f68a8584
2 changed files with 49 additions and 29 deletions
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61
src/backend/access/transam/xact.c
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@ -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 */
}
/* --------------------------------