* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/backend/access/transam/subtrans.c,v 1.1 2004/07/01 00:49:42 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/access/transam/subtrans.c,v 1.2 2004/08/22 02:41:57 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "access/subtrans.h"
#include "miscadmin.h"
#include "storage/lwlock.h"
+#include "utils/tqual.h"
/*
TransactionId *ptr;
TransactionId parent;
+ /* Can't ask about stuff that might not be around anymore */
+ Assert(TransactionIdFollowsOrEquals(xid, RecentXmin));
+
/* Bootstrap and frozen XIDs have no parent */
if (!TransactionIdIsNormal(xid))
return InvalidTransactionId;
* SubTransGetTopmostTransaction
*
* Returns the topmost transaction of the given transaction id.
+ *
+ * Because we cannot look back further than RecentXmin, it is possible
+ * that this function will lie and return an intermediate subtransaction ID
+ * instead of the true topmost parent ID. This is OK, because in practice
+ * we only care about detecting whether the topmost parent is still running
+ * or is part of a current snapshot's list of still-running transactions.
+ * Therefore, any XID before RecentXmin is as good as any other.
*/
TransactionId
SubTransGetTopmostTransaction(TransactionId xid)
TransactionId parentXid = xid,
previousXid = xid;
+ /* Can't ask about stuff that might not be around anymore */
+ Assert(TransactionIdFollowsOrEquals(xid, RecentXmin));
+
while (TransactionIdIsValid(parentXid))
{
previousXid = parentXid;
+ if (TransactionIdPrecedes(parentXid, RecentXmin))
+ break;
parentXid = SubTransGetParent(parentXid);
}
return previousXid;
}
-/*
- * SubTransXidsHaveCommonAncestor
- *
- * Returns true iff the Xids have a common ancestor
- */
-bool
-SubTransXidsHaveCommonAncestor(TransactionId xid1, TransactionId xid2)
-{
- if (TransactionIdEquals(xid1, xid2))
- return true;
-
- while (TransactionIdIsValid(xid1) && TransactionIdIsValid(xid2))
- {
- if (TransactionIdPrecedes(xid2, xid1))
- xid1 = SubTransGetParent(xid1);
- else
- xid2 = SubTransGetParent(xid2);
-
- if (TransactionIdEquals(xid1, xid2))
- return true;
- }
-
- return false;
-}
/*
* Initialization of shared memory for Subtrans
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/access/transam/transam.c,v 1.57 2004/07/01 00:49:42 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/access/transam/transam.c,v 1.58 2004/08/22 02:41:57 tgl Exp $
*
* NOTES
* This file contains the high level access-method interface to the
#include "access/clog.h"
#include "access/subtrans.h"
#include "access/transam.h"
+#include "utils/tqual.h"
/* ----------------
/*
* If it's marked subcommitted, we have to check the parent recursively.
+ * However, if it's older than RecentXmin, we can't look at pg_subtrans;
+ * instead assume that the parent crashed without cleaning up its children.
*/
if (xidstatus == TRANSACTION_STATUS_SUB_COMMITTED)
{
TransactionId parentXid;
-
+
+ if (TransactionIdPrecedes(transactionId, RecentXmin))
+ return false;
parentXid = SubTransGetParent(transactionId);
Assert(TransactionIdIsValid(parentXid));
return TransactionIdDidCommit(parentXid);
/*
* If it's marked subcommitted, we have to check the parent recursively.
- *
- * If we detect that the parent has aborted, update pg_clog to show the
- * subtransaction as aborted. This is only needed when the parent
- * crashed before either committing or aborting. We want to clean up
- * pg_clog so future visitors don't need to make this check again.
+ * However, if it's older than RecentXmin, we can't look at pg_subtrans;
+ * instead assume that the parent crashed without cleaning up its children.
*/
if (xidstatus == TRANSACTION_STATUS_SUB_COMMITTED)
{
TransactionId parentXid;
- bool parentAborted;
-
- parentXid = SubTransGetParent(transactionId);
- parentAborted = TransactionIdDidAbort(parentXid);
- if (parentAborted)
- TransactionIdAbort(transactionId);
-
- return parentAborted;
+ if (TransactionIdPrecedes(transactionId, RecentXmin))
+ return true;
+ parentXid = SubTransGetParent(transactionId);
+ return TransactionIdDidAbort(parentXid);
}
/*
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/storage/ipc/sinval.c,v 1.68 2004/08/15 17:03:36 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/storage/ipc/sinval.c,v 1.69 2004/08/22 02:41:57 tgl Exp $
*
*-------------------------------------------------------------------------
*/
/*
* Don't bother checking a very old transaction.
*/
- if (TransactionIdPrecedes(xid, RecentGlobalXmin))
+ if (TransactionIdPrecedes(xid, RecentXmin))
{
xc_by_recent_xmin_inc();
return false;
return count;
}
+#ifdef NOT_USED
/*
* GetUndoRecPtr -- returns oldest PGPROC->logRec.
*/
return (urec);
}
+#endif /* NOT_USED */
/*
* BackendIdGetProc - given a BackendId, find its PGPROC structure
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/storage/lmgr/lmgr.c,v 1.66 2004/07/28 14:23:29 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/storage/lmgr/lmgr.c,v 1.67 2004/08/22 02:41:57 tgl Exp $
*
*-------------------------------------------------------------------------
*/
LOCKTAG tag;
TransactionId myxid = GetTopTransactionId();
- Assert(!SubTransXidsHaveCommonAncestor(xid, myxid));
+ Assert(!TransactionIdEquals(xid, myxid));
MemSet(&tag, 0, sizeof(tag));
tag.relId = XactLockTableId;
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/utils/time/tqual.c,v 1.74 2004/07/28 14:23:30 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/time/tqual.c,v 1.75 2004/08/22 02:41:57 tgl Exp $
*
*-------------------------------------------------------------------------
*/
{
if (tuple->t_infomask & HEAP_XMAX_INVALID) /* xid invalid */
return HEAPTUPLE_INSERT_IN_PROGRESS;
- Assert(SubTransXidsHaveCommonAncestor(HeapTupleHeaderGetXmin(tuple),
- HeapTupleHeaderGetXmax(tuple)));
if (tuple->t_infomask & HEAP_MARKED_FOR_UPDATE)
return HEAPTUPLE_INSERT_IN_PROGRESS;
/* inserted and then deleted by same xact */
* Deleter committed, but check special cases.
*/
- if (SubTransXidsHaveCommonAncestor(HeapTupleHeaderGetXmin(tuple),
+ if (TransactionIdEquals(HeapTupleHeaderGetXmin(tuple),
HeapTupleHeaderGetXmax(tuple)))
{
/*
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/access/subtrans.h,v 1.1 2004/07/01 00:51:38 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/access/subtrans.h,v 1.2 2004/08/22 02:41:58 tgl Exp $
*/
#ifndef SUBTRANS_H
#define SUBTRANS_H
extern void SubTransSetParent(TransactionId xid, TransactionId parent);
extern TransactionId SubTransGetParent(TransactionId xid);
extern TransactionId SubTransGetTopmostTransaction(TransactionId xid);
-extern bool SubTransXidsHaveCommonAncestor(TransactionId xid1, TransactionId xid2);
extern int SUBTRANSShmemSize(void);
extern void SUBTRANSShmemInit(void);
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/access/xlog.h,v 1.54 2004/07/21 22:31:25 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/access/xlog.h,v 1.55 2004/08/22 02:41:58 tgl Exp $
*/
#ifndef XLOG_H
#define XLOG_H
extern void XLogPutNextOid(Oid nextOid);
extern XLogRecPtr GetRedoRecPtr(void);
-/* in storage/ipc/sinval.c, but don't want to declare in sinval.h because
- * we'd have to include xlog.h into that ...
- */
-extern XLogRecPtr GetUndoRecPtr(void);
-
#endif /* XLOG_H */
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