Ensure that before truncating CLOG, we force a checkpoint even if no

recent WAL activity has occurred.  Without this, it's possible that a
later crash might leave tuples on disk with un-updated commit status
bits.

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 4b935492ea59798484bea2f1389d280741ba9140..b72fb5d651ed3e7ff461d4da7de955f5a67a53dd 100644 (file)
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -13,7 +13,7 @@
  * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Header: /cvsroot/pgsql/src/backend/access/transam/clog.c,v 1.10 2002/09/02 02:47:01 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/access/transam/clog.c,v 1.11 2002/09/26 22:58:33 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -809,8 +809,8 @@ TruncateCLOG(TransactionId oldestXact)
    if (!ScanCLOGDirectory(cutoffPage, false))
        return;                 /* nothing to remove */
 
-   /* Perform a CHECKPOINT */
-   CreateCheckPoint(false);
+   /* Perform a forced CHECKPOINT */
+   CreateCheckPoint(false, true);
 
    /*
     * Scan CLOG shared memory and remove any pages preceding the cutoff

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 0ff60292e68324563979d397dfcd6080a312a7d7..1944e557708f5cc31d8cc839187ecc56361e9ca3 100644 (file)
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Header: /cvsroot/pgsql/src/backend/access/transam/xlog.c,v 1.106 2002/09/04 20:31:13 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/access/transam/xlog.c,v 1.107 2002/09/26 22:58:33 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2743,7 +2743,7 @@ StartupXLOG(void)
         * checkpoint to become prevCheckPoint...
         */
        ControlFile->checkPoint = checkPointLoc;
-       CreateCheckPoint(true);
+       CreateCheckPoint(true, true);
        XLogCloseRelationCache();
    }
 
@@ -2901,7 +2901,7 @@ ShutdownXLOG(void)
 
    CritSectionCount++;
    CreateDummyCaches();
-   CreateCheckPoint(true);
+   CreateCheckPoint(true, true);
    ShutdownCLOG();
    CritSectionCount--;
 
@@ -2910,9 +2910,12 @@ ShutdownXLOG(void)
 
 /*
  * Perform a checkpoint --- either during shutdown, or on-the-fly
+ *
+ * If force is true, we force a checkpoint regardless of whether any XLOG
+ * activity has occurred since the last one.
  */
 void
-CreateCheckPoint(bool shutdown)
+CreateCheckPoint(bool shutdown, bool force)
 {
    CheckPoint  checkPoint;
    XLogRecPtr  recptr;
@@ -2955,21 +2958,21 @@ CreateCheckPoint(bool shutdown)
    LWLockAcquire(WALInsertLock, LW_EXCLUSIVE);
 
    /*
-    * If this isn't a shutdown, and we have not inserted any XLOG records
-    * since the start of the last checkpoint, skip the checkpoint.  The
-    * idea here is to avoid inserting duplicate checkpoints when the
-    * system is idle.  That wastes log space, and more importantly it
+    * If this isn't a shutdown or forced checkpoint, and we have not inserted
+    * any XLOG records since the start of the last checkpoint, skip the
+    * checkpoint.  The idea here is to avoid inserting duplicate checkpoints
+    * when the system is idle. That wastes log space, and more importantly it
     * exposes us to possible loss of both current and previous checkpoint
     * records if the machine crashes just as we're writing the update.
-    * (Perhaps it'd make even more sense to checkpoint only when the
-    * previous checkpoint record is in a different xlog page?)
+    * (Perhaps it'd make even more sense to checkpoint only when the previous
+    * checkpoint record is in a different xlog page?)
     *
     * We have to make two tests to determine that nothing has happened since
     * the start of the last checkpoint: current insertion point must
     * match the end of the last checkpoint record, and its redo pointer
     * must point to itself.
     */
-   if (!shutdown)
+   if (!shutdown && !force)
    {
        XLogRecPtr  curInsert;
 

diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 4df563b4285a51f2d7f1e71196504c97b756c8d5..a2b26bcdb00d506de0fd0057a405db3d2b4cf410 100644 (file)
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/bootstrap/bootstrap.c,v 1.143 2002/09/25 20:31:40 tgl Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/bootstrap/bootstrap.c,v 1.144 2002/09/26 22:58:33 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -390,7 +390,7 @@ BootstrapMain(int argc, char *argv[])
 
        case BS_XLOG_CHECKPOINT:
            CreateDummyCaches();
-           CreateCheckPoint(false);
+           CreateCheckPoint(false, false);
            SetSavedRedoRecPtr();       /* pass redo ptr back to
                                         * postmaster */
            proc_exit(0);       /* done */
@@ -445,7 +445,7 @@ BootstrapMain(int argc, char *argv[])
    Int_yyparse();
 
    SetProcessingMode(NormalProcessing);
-   CreateCheckPoint(true);
+   CreateCheckPoint(true, true);
    SetProcessingMode(BootstrapProcessing);
 
    /* clean up processing */

diff --git a/src/backend/tcop/utility.c b/src/backend/tcop/utility.c
index 92d876b265bab8b8b768c1b64bbee37612c713c7..c6bd3050825bb5fa6c14e82698aee84d33f6f91e 100644 (file)
--- a/src/backend/tcop/utility.c
+++ b/src/backend/tcop/utility.c
@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/tcop/utility.c,v 1.177 2002/09/04 20:31:26 momjian Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/tcop/utility.c,v 1.178 2002/09/26 22:58:33 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -831,11 +831,9 @@ ProcessUtility(Node *parsetree,
            break;
 
        case T_CheckPointStmt:
-           {
-               if (!superuser())
-                   elog(ERROR, "permission denied");
-               CreateCheckPoint(false);
-           }
+           if (!superuser())
+               elog(ERROR, "permission denied");
+           CreateCheckPoint(false, false);
            break;
 
        case T_ReindexStmt:

diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index c8c49936803e1fc1318fc1991a587703d333ed22..f5c3e59cbcef9ab7211d8d9af29b68ed1ccd7f19 100644 (file)
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: xlog.h,v 1.38 2002/09/26 22:46:29 tgl Exp $
+ * $Id: xlog.h,v 1.39 2002/09/26 22:58:34 tgl Exp $
  */
 #ifndef XLOG_H
 #define XLOG_H
@@ -204,7 +204,7 @@ extern void XLOGPathInit(void);
 extern void BootStrapXLOG(void);
 extern void StartupXLOG(void);
 extern void ShutdownXLOG(void);
-extern void CreateCheckPoint(bool shutdown);
+extern void CreateCheckPoint(bool shutdown, bool force);
 extern void SetThisStartUpID(void);
 extern void XLogPutNextOid(Oid nextOid);
 extern void SetSavedRedoRecPtr(void);