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btree page recycling can be done as soon as page's next-xact label is

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older than current Xmin; we don't have to wait till it's older than
GlobalXmin.
This commit is contained in:
Tom Lane 2003-02-23 23:20:52 +00:00
parent 3bbd6af37c
commit 61b22d3aab
4 changed files with 13 additions and 8 deletions
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4
src/backend/access/nbtree/nbtpage.c
View File

@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtpage.c,v 1.62 2003/02/23 22:43:08 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtpage.c,v 1.63 2003/02/23 23:20:52 tgl Exp $
*
* NOTES
* Postgres btree pages look like ordinary relation pages. The opaque
@ -544,7 +544,7 @@ _bt_page_recyclable(Page page)
*/
opaque = (BTPageOpaque) PageGetSpecialPointer(page);
if (P_ISDELETED(opaque) &&
TransactionIdPrecedesOrEquals(opaque->btpo.xact, RecentGlobalXmin))
TransactionIdPrecedesOrEquals(opaque->btpo.xact, RecentXmin))
return true;
return false;
}

9
src/backend/storage/ipc/sinval.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/storage/ipc/sinval.c,v 1.53 2002/11/21 06:36:08 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/storage/ipc/sinval.c,v 1.54 2003/02/23 23:20:52 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -298,9 +298,10 @@ GetOldestXmin(bool allDbs)
* This ensures that the set of transactions seen as "running" by the
* current xact will not change after it takes the snapshot.
*
* Also, we compute the current global xmin (oldest xmin across all running
* We also compute the current global xmin (oldest xmin across all running
* transactions) and save it in RecentGlobalXmin. This is the same
* computation done by GetOldestXmin(TRUE).
* computation done by GetOldestXmin(TRUE). The xmin value is also stored
* into RecentXmin.
*----------
*/
Snapshot
@ -419,7 +420,9 @@ GetSnapshotData(bool serializable)
if (TransactionIdPrecedes(xmin, globalxmin))
globalxmin = xmin;
/* Update globals for use by VACUUM */
RecentGlobalXmin = globalxmin;
RecentXmin = xmin;
snapshot->xmin = xmin;
snapshot->xmax = xmax;

5
src/backend/utils/time/tqual.c
View File

@ -16,7 +16,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/time/tqual.c,v 1.61 2002/10/08 17:17:19 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/time/tqual.c,v 1.62 2003/02/23 23:20:52 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -33,7 +33,8 @@ Snapshot SnapshotDirty = &SnapshotDirtyData;
Snapshot QuerySnapshot = NULL;
Snapshot SerializableSnapshot = NULL;
/* This is updated by GetSnapshotData: */
/* These are updated by GetSnapshotData: */
TransactionId RecentXmin = InvalidTransactionId;
TransactionId RecentGlobalXmin = InvalidTransactionId;
bool ReferentialIntegritySnapshotOverride = false;

3
src/include/utils/tqual.h
View File

@ -8,7 +8,7 @@
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Id: tqual.h,v 1.43 2002/09/04 20:31:46 momjian Exp $
* $Id: tqual.h,v 1.44 2003/02/23 23:20:52 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -41,6 +41,7 @@ extern DLLIMPORT Snapshot SnapshotDirty;
extern DLLIMPORT Snapshot QuerySnapshot;
extern DLLIMPORT Snapshot SerializableSnapshot;
extern TransactionId RecentXmin;
extern TransactionId RecentGlobalXmin;
extern bool ReferentialIntegritySnapshotOverride;