Re: [HACKERS] pg_upgrade - Mailing list pgsql-patches

Bruce Momjian wrote:
> Tom asked about pg_upgrade as part of our initdb for timezone.
>
> I have made some improvements to pg_upgrade in CVS and have successfully
> migrated a regression database from a 7.2 to another 7.2 database using
> it.  (At least the tables show some data;  very light testing.)

Here is a patch I need to /contrib/pg_resetxlog to support a new "-x
XID" option to set the XID in pg_control.  Patch attached.  This is the
last feature I needed for a functioning pg_upgrade for 7.1->7.2 and
7.2->7.2 databases.

Many commercial distributions like this script, and with our
newly-needed initdb to fix our timezonetz problem, it seemed like a good
time.  :-)  It certainly reduces upgrade time.

(BTW, where are we on that timezonetz patch anyway?  Tom posted it two
days ago and I haven't seen any comments.)

pg_upgrade is still disabled.

--
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026
Index: contrib/pg_resetxlog/README.pg_resetxlog
===================================================================
RCS file: /cvsroot/pgsql/contrib/pg_resetxlog/README.pg_resetxlog,v
retrieving revision 1.1
diff -c -r1.1 README.pg_resetxlog
*** contrib/pg_resetxlog/README.pg_resetxlog    2001/03/14 00:57:43    1.1
--- contrib/pg_resetxlog/README.pg_resetxlog    2002/01/10 06:09:04
***************
*** 21,26 ****
--- 21,29 ----
  Then run pg_resetxlog, and finally install and start the new version of
  the database software.

+ A tertiary purpose it its use by pg_upgrade to set the next transaction
+ id in pg_control.
+
  To run the program, make sure your postmaster is not running, then
  (as the Postgres admin user) do

Index: contrib/pg_resetxlog/pg_resetxlog.c
===================================================================
RCS file: /cvsroot/pgsql/contrib/pg_resetxlog/pg_resetxlog.c,v
retrieving revision 1.10
diff -c -r1.10 pg_resetxlog.c
*** contrib/pg_resetxlog/pg_resetxlog.c    2001/11/05 17:46:23    1.10
--- contrib/pg_resetxlog/pg_resetxlog.c    2002/01/10 06:09:05
***************
*** 709,742 ****
   * Write out the new pg_control file.
   */
  static void
! RewriteControlFile(void)
  {
      int            fd;
      char        buffer[BLCKSZ]; /* need not be aligned */

!     /*
!      * Adjust fields as needed to force an empty XLOG starting at the next
!      * available segment.
!      */
!     newXlogId = ControlFile.logId;
!     newXlogSeg = ControlFile.logSeg;
!     /* be sure we wrap around correctly at end of a logfile */
!     NextLogSeg(newXlogId, newXlogSeg);
!
!     ControlFile.checkPointCopy.redo.xlogid = newXlogId;
!     ControlFile.checkPointCopy.redo.xrecoff =
!         newXlogSeg * XLogSegSize + SizeOfXLogPHD;
!     ControlFile.checkPointCopy.undo = ControlFile.checkPointCopy.redo;
!     ControlFile.checkPointCopy.time = time(NULL);
!
!     ControlFile.state = DB_SHUTDOWNED;
!     ControlFile.time = time(NULL);
!     ControlFile.logId = newXlogId;
!     ControlFile.logSeg = newXlogSeg + 1;
!     ControlFile.checkPoint = ControlFile.checkPointCopy.redo;
!     ControlFile.prevCheckPoint.xlogid = 0;
!     ControlFile.prevCheckPoint.xrecoff = 0;
!
      /* Contents are protected with a CRC */
      INIT_CRC64(ControlFile.crc);
      COMP_CRC64(ControlFile.crc,
--- 709,747 ----
   * Write out the new pg_control file.
   */
  static void
! RewriteControlFile(TransactionId set_xid)
  {
      int            fd;
      char        buffer[BLCKSZ]; /* need not be aligned */

!     if (set_xid == 0)
!     {
!         /*
!          * Adjust fields as needed to force an empty XLOG starting at the next
!          * available segment.
!          */
!         newXlogId = ControlFile.logId;
!         newXlogSeg = ControlFile.logSeg;
!         /* be sure we wrap around correctly at end of a logfile */
!         NextLogSeg(newXlogId, newXlogSeg);
!
!         ControlFile.checkPointCopy.redo.xlogid = newXlogId;
!         ControlFile.checkPointCopy.redo.xrecoff =
!             newXlogSeg * XLogSegSize + SizeOfXLogPHD;
!         ControlFile.checkPointCopy.undo = ControlFile.checkPointCopy.redo;
!         ControlFile.checkPointCopy.time = time(NULL);
!
!         ControlFile.state = DB_SHUTDOWNED;
!         ControlFile.time = time(NULL);
!         ControlFile.logId = newXlogId;
!         ControlFile.logSeg = newXlogSeg + 1;
!         ControlFile.checkPoint = ControlFile.checkPointCopy.redo;
!         ControlFile.prevCheckPoint.xlogid = 0;
!         ControlFile.prevCheckPoint.xrecoff = 0;
!     }
!     else
!         ControlFile.checkPointCopy.nextXid = set_xid;
!
      /* Contents are protected with a CRC */
      INIT_CRC64(ControlFile.crc);
      COMP_CRC64(ControlFile.crc,
***************
*** 926,934 ****
  static void
  usage(void)
  {
!     fprintf(stderr, "Usage: pg_resetxlog [-f] [-n] PGDataDirectory\n\n"
!             "  -f\tforce update to be done\n"
!             "  -n\tno update, just show extracted pg_control values (for testing)\n");
      exit(1);
  }

--- 931,940 ----
  static void
  usage(void)
  {
!     fprintf(stderr, "Usage: pg_resetxlog [-f] [-n] [-x xid] PGDataDirectory\n"
!             " -f\tforce update to be done\n"
!             " -n\tno update, just show extracted pg_control values (for testing)\n"
!             " -x XID\tset XID in pg_control\n");
      exit(1);
  }

***************
*** 939,944 ****
--- 945,951 ----
      int            argn;
      bool        force = false;
      bool        noupdate = false;
+     TransactionId set_xid = 0;
      int            fd;
      char        path[MAXPGPATH];

***************
*** 950,955 ****
--- 957,974 ----
              force = true;
          else if (strcmp(argv[argn], "-n") == 0)
              noupdate = true;
+         else if (strcmp(argv[argn], "-x") == 0)
+         {
+             argn++;
+             if (argn == argc)
+                 usage();
+             set_xid = strtoul(argv[argn], NULL, 0);
+             if (set_xid == 0)
+             {
+                 fprintf(stderr, "XID can not be 0.");
+                 exit(1);
+             }
+         }
          else
              usage();
      }
***************
*** 993,998 ****
--- 1012,1031 ----
          GuessControlValues();

      /*
+      * Set XID in pg_control and exit
+      */
+     if (set_xid)
+     {
+         if (guessed)
+         {
+             printf("\npg_control appears corrupt.  Can not update XID.\n");
+             exit(1);
+         }
+         RewriteControlFile(set_xid);
+         exit(0);
+     }
+
+     /*
       * If we had to guess anything, and -f was not given, just print the
       * guessed values and exit.  Also print if -n is given.
       */
***************
*** 1018,1024 ****
      /*
       * Else, do the dirty deed.
       */
!     RewriteControlFile();
      KillExistingXLOG();
      WriteEmptyXLOG();

--- 1051,1057 ----
      /*
       * Else, do the dirty deed.
       */
!     RewriteControlFile(0);
      KillExistingXLOG();
      WriteEmptyXLOG();