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1. MyProc->xid assignment is moved to GetNewTransactionId so newer

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transactions will not assume that MyProc transaction was committed
   before snapshot calculations. With old MyProc->xid assignment
   (in xact.c:StartTransaction()) there was ability to see the same
   row twice (I used gdb for this)!...
2. Assignments of InvalidTransactionId to MyProc->xid and MyProc->xmin
   are moved from xact.c:CommitTransaction() to
   xact.c:RecordTransactionCommit() - this invalidation must be done
   before releasing transaction locks or bad (too high) XmaxRecent value
   might be used by vacuum ("ERROR:  Child itemid marked as unused"
   reported by "Hiroshi Inoue" <Inoue@tpf.co.jp>; once again, gdb
   allowed me reproduce this error).
This commit is contained in:
Vadim B. Mikheev 1999-06-03 04:41:41 +00:00
parent f3d2b2e0c7
commit 9680a71205
2 changed files with 18 additions and 18 deletions
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6
src/backend/access/transam/varsup.c
View File

@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/access/transam/varsup.c,v 1.20 1999/05/25 16:07:48 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/access/transam/varsup.c,v 1.21 1999/06/03 04:41:40 vadim Exp $
*
*-------------------------------------------------------------------------
*/
@ -19,6 +19,7 @@
#include <access/xact.h>
#include <access/heapam.h>
#include <catalog/catname.h>
#include <storage/proc.h>
static void GetNewObjectIdBlock(Oid *oid_return, int oid_block_size);
static void VariableRelationGetNextOid(Oid *oid_return);
@ -308,6 +309,9 @@ GetNewTransactionId(TransactionId *xid)
TransactionIdAdd(&(ShmemVariableCache->nextXid), 1);
(ShmemVariableCache->xid_count)--;
if (MyProc != (PROC *) NULL)
MyProc->xid = *xid;
SpinRelease(OidGenLockId);
}

30
src/backend/access/transam/xact.c
View File

@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/access/transam/xact.c,v 1.37 1999/05/31 22:53:59 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/access/transam/xact.c,v 1.38 1999/06/03 04:41:41 vadim Exp $
*
* NOTES
* Transaction aborts can now occur two ways:
@ -646,6 +646,18 @@ RecordTransactionCommit()
FlushBufferPool(!TransactionFlushEnabled());
if (leak)
ResetBufferPool();
/*
* Let others know about no transaction in progress.
* Note that this must be done _before_ releasing locks
* we hold or bad (too high) XmaxRecent value might be
* used by vacuum.
*/
if (MyProc != (PROC *) NULL)
{
MyProc->xid = InvalidTransactionId;
MyProc->xmin = InvalidTransactionId;
}
}
@ -884,13 +896,6 @@ StartTransaction()
*/
s->state = TRANS_INPROGRESS;
/*
* Let others to know about current transaction is in progress - vadim
* 11/26/96
*/
if (MyProc != (PROC *) NULL)
MyProc->xid = s->transactionIdData;
}
/* ---------------
@ -958,15 +963,6 @@ CommitTransaction()
*/
s->state = TRANS_DEFAULT;
/*
* Let others to know about no transaction in progress - vadim
* 11/26/96
*/
if (MyProc != (PROC *) NULL)
{
MyProc->xid = InvalidTransactionId;
MyProc->xmin = InvalidTransactionId;
}
}
/* --------------------------------