From f8409b39d1dae28f063b378b9edee1a657845503 Mon Sep 17 00:00:00 2001
From: Simon Riggs <simon@2ndQuadrant.com>
Date: Wed, 2 Nov 2011 08:07:44 +0000
Subject: [PATCH] Fix timing of Startup CLOG and MultiXact during Hot Standby
Patch by me, bug report by Chris Redekop, analysis by Florian Pflug
---
src/backend/access/transam/clog.c | 19 +++++++++++++++++++
src/backend/access/transam/multixact.c | 2 +-
src/backend/access/transam/xlog.c | 17 ++++++++++++-----
src/backend/utils/init/postinit.c | 1 +
src/include/access/clog.h | 1 +
5 files changed, 34 insertions(+), 6 deletions(-)
diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index ee645f7bd47..6a2bf83362f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -489,6 +489,25 @@ StartupCLOG(void)
*/
ClogCtl->shared->latest_page_number = pageno;
+ LWLockRelease(CLogControlLock);
+}
+
+/*
+ * This must be called ONCE at the end of startup/recovery.
+ */
+void
+TrimCLOG(void)
+{
+ TransactionId xid = ShmemVariableCache->nextXid;
+ int pageno = TransactionIdToPage(xid);
+
+ LWLockAcquire(CLogControlLock, LW_EXCLUSIVE);
+
+ /*
+ * Re-Initialize our idea of the latest page number.
+ */
+ ClogCtl->shared->latest_page_number = pageno;
+
/*
* Zero out the remainder of the current clog page. Under normal
* circumstances it should be zeroes already, but it seems at least
diff --git a/src/backend/access/transam/multixact.c b/src/backend/access/transam/multixact.c
index 1d159bc89cb..c1c8ba52da3 100644
--- a/src/backend/access/transam/multixact.c
+++ b/src/backend/access/transam/multixact.c
@@ -1567,7 +1567,7 @@ StartupMultiXact(void)
/*
* Zero out the remainder of the current members page. See notes in
- * StartupCLOG() for motivation.
+ * TrimCLOG() for motivation.
*/
entryno = MXOffsetToMemberEntry(offset);
if (entryno != 0)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index a6aee9eb30c..bf57b3bf49e 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -6410,10 +6410,12 @@ StartupXLOG(void)
oldestActiveXID = checkPoint.oldestActiveXid;
Assert(TransactionIdIsValid(oldestActiveXID));
- /* Startup commit log and related stuff */
+ /*
+ * Startup commit log and subtrans only. Other SLRUs are not
+ * maintained during recovery and need not be started yet.
+ */
StartupCLOG();
StartupSUBTRANS(oldestActiveXID);
- StartupMultiXact();
/*
* If we're beginning at a shutdown checkpoint, we know that
@@ -6914,16 +6916,21 @@ StartupXLOG(void)
TransactionIdRetreat(ShmemVariableCache->latestCompletedXid);
/*
- * Start up the commit log and related stuff, too. In hot standby mode we
- * did this already before WAL replay.
+ * Start up the commit log and subtrans, if not already done for
+ * hot standby.
*/
if (standbyState == STANDBY_DISABLED)
{
StartupCLOG();
StartupSUBTRANS(oldestActiveXID);
- StartupMultiXact();
}
+ /*
+ * Perform end of recovery actions for any SLRUs that need it.
+ */
+ StartupMultiXact();
+ TrimCLOG();
+
/* Reload shared-memory state for prepared transactions */
RecoverPreparedTransactions();
diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c
index 94f92dd7343..0fda55af0fc 100644
--- a/src/backend/utils/init/postinit.c
+++ b/src/backend/utils/init/postinit.c
@@ -36,6 +36,7 @@
#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "postmaster/postmaster.h"
+#include "postmaster/startup.h"
#include "replication/walsender.h"
#include "storage/bufmgr.h"
#include "storage/fd.h"
diff --git a/src/include/access/clog.h b/src/include/access/clog.h
index 7a8918e0fc5..691430c97ca 100644
--- a/src/include/access/clog.h
+++ b/src/include/access/clog.h
@@ -40,6 +40,7 @@ extern Size CLOGShmemSize(void);
extern void CLOGShmemInit(void);
extern void BootStrapCLOG(void);
extern void StartupCLOG(void);
+extern void TrimCLOG(void);
extern void ShutdownCLOG(void);
extern void CheckPointCLOG(void);
extern void ExtendCLOG(TransactionId newestXact);
--
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