postgres.git / summary / log / commit / refs

commit    3d974e303da29ff97822212ab8722d6e366c5119
Author:   Alvaro Herrera <alvherre@alvh.no-ip.org>
Date:     Mon Dec 02 16:28:10 2013 +0000
First released in: 9.0.15, 9.1.11, 9.2.6

    Fix incomplete backpatch of pg_multixact truncation changes to <= 9.2
    
    The backpatch of a95335b544d9c8377e9dc7a399d8e9a155895f82 to 9.2, 9.1
    and 9.0 was incomplete, missing changes to xlog.c, primarily the call
    to TrimMultiXact(). Testing presumably didn't show a problem without
    these changes because TrimMultiXact() performs defense-in-depth work,
    which is not strictly necessary.
    
    It also missed moving StartupMultiXact() which would have been
    problematic if a restartpoing happened in exactly the wrong moment,
    causing a transient error.
    
    Andres Freund


 src/backend/access/transam/xlog.c | 13 ++++++++++---
 src/include/access/multixact.h    |  1 +
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 47ecdac5fee..c69130a3c5d 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -5991,6 +5991,12 @@ StartupXLOG(void)
 	XLogCtl->ckptXidEpoch = checkPoint.nextXidEpoch;
 	XLogCtl->ckptXid = checkPoint.nextXid;
 
+	/*
+	 * Startup MultiXact.  We need to do this early because we need its state
+	 * initialized because we attempt truncation during restartpoints.
+	 */
+	StartupMultiXact();
+
 	/*
 	 * We must replay WAL entries using the same TimeLineID they were created
 	 * under, so temporarily adopt the TLI indicated by the checkpoint (see
@@ -6121,8 +6127,9 @@ StartupXLOG(void)
 			ProcArrayInitRecovery(ShmemVariableCache->nextXid);
 
 			/*
-			 * Startup commit log and subtrans only. Other SLRUs are not
-			 * maintained during recovery and need not be started yet.
+			 * Startup commit log and subtrans only. MultiXact has already
+			 * been started up and other SLRUs are not maintained during
+			 * recovery and need not be started yet.
 			 */
 			StartupCLOG();
 			StartupSUBTRANS(oldestActiveXID);
@@ -6593,7 +6600,7 @@ StartupXLOG(void)
 	/*
 	 * Perform end of recovery actions for any SLRUs that need it.
 	 */
-	StartupMultiXact();
+	TrimMultiXact();
 	TrimCLOG();
 
 	/* Reload shared-memory state for prepared transactions */
diff --git a/src/include/access/multixact.h b/src/include/access/multixact.h
index c9a3a3d52db..3a21033f535 100644
--- a/src/include/access/multixact.h
+++ b/src/include/access/multixact.h
@@ -59,6 +59,7 @@ extern Size MultiXactShmemSize(void);
 extern void MultiXactShmemInit(void);
 extern void BootStrapMultiXact(void);
 extern void StartupMultiXact(void);
+extern void TrimMultiXact(void);
 extern void ShutdownMultiXact(void);
 extern void MultiXactGetCheckptMulti(bool is_shutdown,
 						 MultiXactId *nextMulti,


[parent: 8269e4091c45]