Re: What is CheckPoint.undo needed for? - Mailing list pgsql-hackers

Patch applied.  Thanks.

---------------------------------------------------------------------------


Florian G. Pflug wrote:
> Tom Lane wrote:
> > Alvaro Herrera <alvherre@commandprompt.com> writes:
> >> I think you should increase pg_control version.
> > 
> > And the WAL page-header version, since this also changes WAL contents.
> 
> Here is an updated version. I've incremeted XLOG_PAGE_MAGIC and
> PG_CONTROL_VERSION by one.
> 
> greetings, Florian Pflug
> 

> Index: src/backend/access/transam/xlog.c
> ===================================================================
> RCS file: /projects/cvsroot/pgsql/src/backend/access/transam/xlog.c,v
> retrieving revision 1.264
> diff -a -u -r1.264 xlog.c
> --- src/backend/access/transam/xlog.c    14 Feb 2007 05:00:40 -0000    1.264
> +++ src/backend/access/transam/xlog.c    23 Feb 2007 15:09:09 -0000
> @@ -4039,7 +4039,6 @@
>      /* Set up information for the initial checkpoint record */
>      checkPoint.redo.xlogid = 0;
>      checkPoint.redo.xrecoff = SizeOfXLogLongPHD;
> -    checkPoint.undo = checkPoint.redo;
>      checkPoint.ThisTimeLineID = ThisTimeLineID;
>      checkPoint.nextXidEpoch = 0;
>      checkPoint.nextXid = FirstNormalTransactionId;
> @@ -4698,9 +4697,8 @@
>      wasShutdown = (record->xl_info == XLOG_CHECKPOINT_SHUTDOWN);
>  
>      ereport(LOG,
> -     (errmsg("redo record is at %X/%X; undo record is at %X/%X; shutdown %s",
> +     (errmsg("redo record is at %X/%X; shutdown %s",
>               checkPoint.redo.xlogid, checkPoint.redo.xrecoff,
> -             checkPoint.undo.xlogid, checkPoint.undo.xrecoff,
>               wasShutdown ? "TRUE" : "FALSE")));
>      ereport(LOG,
>              (errmsg("next transaction ID: %u/%u; next OID: %u",
> @@ -4730,20 +4728,17 @@
>      if (XLByteLT(RecPtr, checkPoint.redo))
>          ereport(PANIC,
>                  (errmsg("invalid redo in checkpoint record")));
> -    if (checkPoint.undo.xrecoff == 0)
> -        checkPoint.undo = RecPtr;
>  
>      /*
>       * Check whether we need to force recovery from WAL.  If it appears to
>       * have been a clean shutdown and we did not have a recovery.conf file,
>       * then assume no recovery needed.
>       */
> -    if (XLByteLT(checkPoint.undo, RecPtr) ||
> -        XLByteLT(checkPoint.redo, RecPtr))
> +    if (XLByteLT(checkPoint.redo, RecPtr))
>      {
>          if (wasShutdown)
>              ereport(PANIC,
> -                (errmsg("invalid redo/undo record in shutdown checkpoint")));
> +                (errmsg("invalid redo record in shutdown checkpoint")));
>          InRecovery = true;
>      }
>      else if (ControlFile->state != DB_SHUTDOWNED)
> @@ -5850,10 +5845,9 @@
>      {
>          CheckPoint *checkpoint = (CheckPoint *) rec;
>  
> -        appendStringInfo(buf, "checkpoint: redo %X/%X; undo %X/%X; "
> +        appendStringInfo(buf, "checkpoint: redo %X/%X; "
>                           "tli %u; xid %u/%u; oid %u; multi %u; offset %u; %s",
>                           checkpoint->redo.xlogid, checkpoint->redo.xrecoff,
> -                         checkpoint->undo.xlogid, checkpoint->undo.xrecoff,
>                           checkpoint->ThisTimeLineID,
>                           checkpoint->nextXidEpoch, checkpoint->nextXid,
>                           checkpoint->nextOid,
> Index: src/bin/pg_controldata/pg_controldata.c
> ===================================================================
> RCS file: /projects/cvsroot/pgsql/src/bin/pg_controldata/pg_controldata.c,v
> retrieving revision 1.32
> diff -a -u -r1.32 pg_controldata.c
> --- src/bin/pg_controldata/pg_controldata.c    8 Dec 2006 19:50:53 -0000    1.32
> +++ src/bin/pg_controldata/pg_controldata.c    23 Feb 2007 15:09:09 -0000
> @@ -168,9 +168,6 @@
>      printf(_("Latest checkpoint's REDO location:    %X/%X\n"),
>             ControlFile.checkPointCopy.redo.xlogid,
>             ControlFile.checkPointCopy.redo.xrecoff);
> -    printf(_("Latest checkpoint's UNDO location:    %X/%X\n"),
> -           ControlFile.checkPointCopy.undo.xlogid,
> -           ControlFile.checkPointCopy.undo.xrecoff);
>      printf(_("Latest checkpoint's TimeLineID:       %u\n"),
>             ControlFile.checkPointCopy.ThisTimeLineID);
>      printf(_("Latest checkpoint's NextXID:          %u/%u\n"),
> Index: src/bin/pg_resetxlog/pg_resetxlog.c
> ===================================================================
> RCS file: /projects/cvsroot/pgsql/src/bin/pg_resetxlog/pg_resetxlog.c,v
> retrieving revision 1.57
> diff -a -u -r1.57 pg_resetxlog.c
> --- src/bin/pg_resetxlog/pg_resetxlog.c    10 Feb 2007 14:58:55 -0000    1.57
> +++ src/bin/pg_resetxlog/pg_resetxlog.c    23 Feb 2007 15:09:09 -0000
> @@ -464,7 +464,6 @@
>  
>      ControlFile.checkPointCopy.redo.xlogid = 0;
>      ControlFile.checkPointCopy.redo.xrecoff = SizeOfXLogLongPHD;
> -    ControlFile.checkPointCopy.undo = ControlFile.checkPointCopy.redo;
>      ControlFile.checkPointCopy.ThisTimeLineID = 1;
>      ControlFile.checkPointCopy.nextXidEpoch = 0;
>      ControlFile.checkPointCopy.nextXid = (TransactionId) 514;    /* XXX */
> @@ -600,7 +599,6 @@
>      ControlFile.checkPointCopy.redo.xlogid = newXlogId;
>      ControlFile.checkPointCopy.redo.xrecoff =
>          newXlogSeg * XLogSegSize + SizeOfXLogLongPHD;
> -    ControlFile.checkPointCopy.undo = ControlFile.checkPointCopy.redo;
>      ControlFile.checkPointCopy.time = time(NULL);
>  
>      ControlFile.state = DB_SHUTDOWNED;
> Index: src/include/access/xlog_internal.h
> ===================================================================
> RCS file: /projects/cvsroot/pgsql/src/include/access/xlog_internal.h,v
> retrieving revision 1.18
> diff -a -u -r1.18 xlog_internal.h
> --- src/include/access/xlog_internal.h    5 Jan 2007 22:19:51 -0000    1.18
> +++ src/include/access/xlog_internal.h    23 Feb 2007 15:09:09 -0000
> @@ -71,7 +71,7 @@
>  /*
>   * Each page of XLOG file has a header like this:
>   */
> -#define XLOG_PAGE_MAGIC 0xD05E    /* can be used as WAL version indicator */
> +#define XLOG_PAGE_MAGIC 0xD05F    /* can be used as WAL version indicator */
>  
>  typedef struct XLogPageHeaderData
>  {
> Index: src/include/catalog/pg_control.h
> ===================================================================
> RCS file: /projects/cvsroot/pgsql/src/include/catalog/pg_control.h,v
> retrieving revision 1.35
> diff -a -u -r1.35 pg_control.h
> --- src/include/catalog/pg_control.h    5 Jan 2007 22:19:52 -0000    1.35
> +++ src/include/catalog/pg_control.h    23 Feb 2007 15:09:09 -0000
> @@ -22,7 +22,7 @@
>  
>  
>  /* Version identifier for this pg_control format */
> -#define PG_CONTROL_VERSION    831
> +#define PG_CONTROL_VERSION    832
>  
>  /*
>   * Body of CheckPoint XLOG records.  This is declared here because we keep
> @@ -32,9 +32,6 @@
>  {
>      XLogRecPtr    redo;            /* next RecPtr available when we began to
>                                   * create CheckPoint (i.e. REDO start point) */
> -    XLogRecPtr    undo;            /* first record of oldest in-progress
> -                                 * transaction when we started (i.e. UNDO end
> -                                 * point) */
>      TimeLineID    ThisTimeLineID; /* current TLI */
>      uint32        nextXidEpoch;    /* higher-order bits of nextXid */
>      TransactionId nextXid;        /* next free XID */
> 
> 
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--  Bruce Momjian  <bruce@momjian.us>          http://momjian.us EnterpriseDB
http://www.enterprisedb.com
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