Clog handling on exec'ed backend - Mailing list pgsql-patches

Here is a another patch on the way to exec'ed Unix and Win32.

It basically makes one of the Clog data structures into a shared memory
area when using exec (EXEC_BACKEND is defined).  It passes all the
regression/initdb tests on Unix.

--
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073
Index: src/backend/access/transam/clog.c
===================================================================
RCS file: /cvsroot/pgsql-server/src/backend/access/transam/clog.c,v
retrieving revision 1.14
diff -c -c -r1.14 clog.c
*** src/backend/access/transam/clog.c    2 May 2003 21:59:31 -0000    1.14
--- src/backend/access/transam/clog.c    2 May 2003 22:09:26 -0000
***************
*** 157,163 ****
   * The value is automatically inherited by backends via fork, and
   * doesn't need to be in shared memory.
   */
! static LWLockId ClogBufferLocks[NUM_CLOG_BUFFERS];        /* Per-buffer I/O locks */

  /*
   * ClogDir is set during CLOGShmemInit and does not change thereafter.
--- 157,163 ----
   * The value is automatically inherited by backends via fork, and
   * doesn't need to be in shared memory.
   */
! static LWLockId *ClogBufferLocks;        /* Per-buffer I/O locks */

  /*
   * ClogDir is set during CLOGShmemInit and does not change thereafter.
***************
*** 271,311 ****
  /*
   * Initialization of shared memory for CLOG
   */
-
  int
  CLOGShmemSize(void)
  {
!     return MAXALIGN(sizeof(ClogCtlData) + CLOG_BLCKSZ * NUM_CLOG_BUFFERS);
  }

  void
  CLOGShmemInit(void)
  {
      bool        found;
-     char       *bufptr;
      int            slotno;

      /* this must agree with space requested by CLOGShmemSize() */
!     ClogCtl = (ClogCtlData *)
!         ShmemInitStruct("CLOG Ctl",
!                         MAXALIGN(sizeof(ClogCtlData) +
!                                  CLOG_BLCKSZ * NUM_CLOG_BUFFERS),
!                         &found);
!     Assert(!found);

!     memset(ClogCtl, 0, sizeof(ClogCtlData));

!     bufptr = ((char *) ClogCtl) + sizeof(ClogCtlData);

!     for (slotno = 0; slotno < NUM_CLOG_BUFFERS; slotno++)
!     {
!         ClogCtl->page_buffer[slotno] = bufptr;
!         ClogCtl->page_status[slotno] = CLOG_PAGE_EMPTY;
!         ClogBufferLocks[slotno] = LWLockAssign();
!         bufptr += CLOG_BLCKSZ;
      }

!     /* ClogCtl->latest_page_number will be set later */

      /* Init CLOG directory path */
      snprintf(ClogDir, MAXPGPATH, "%s/pg_clog", DataDir);
--- 271,337 ----
  /*
   * Initialization of shared memory for CLOG
   */
  int
  CLOGShmemSize(void)
  {
!     return MAXALIGN(sizeof(ClogCtlData) + CLOG_BLCKSZ * NUM_CLOG_BUFFERS)
! #ifdef EXEC_BACKEND
!             + MAXALIGN(NUM_CLOG_BUFFERS * sizeof(LWLockId))
! #endif
!     ;
  }

+
  void
  CLOGShmemInit(void)
  {
      bool        found;
      int            slotno;

+     /* Handle ClogCtl */
+
      /* this must agree with space requested by CLOGShmemSize() */
!     ClogCtl = (ClogCtlData *) ShmemInitStruct("CLOG Ctl",
!                 MAXALIGN(sizeof(ClogCtlData) +
!                 CLOG_BLCKSZ * NUM_CLOG_BUFFERS), &found);
!
!     if (!IsUnderPostmaster)
!     /* Initialize ClogCtl shared memory area */
!     {
!         char       *bufptr;

!         Assert(!found);

!         memset(ClogCtl, 0, sizeof(ClogCtlData));

!         bufptr = (char *)ClogCtl + sizeof(ClogCtlData);
!
!         for (slotno = 0; slotno < NUM_CLOG_BUFFERS; slotno++)
!         {
!             ClogCtl->page_buffer[slotno] = bufptr;
!             ClogCtl->page_status[slotno] = CLOG_PAGE_EMPTY;
!             bufptr += CLOG_BLCKSZ;
!         }
!
!         /* ClogCtl->latest_page_number will be set later */
      }
+     else
+         Assert(found);

!     /* Handle ClogBufferLocks */
!
! #ifdef EXEC_BACKEND
!     ClogBufferLocks = (LWLockId *) ShmemInitStruct("CLOG Buffer Locks",
!                         NUM_CLOG_BUFFERS * sizeof(LWLockId), &found);
!     Assert((!found && !IsUnderPostmaster) || (found && IsUnderPostmaster));
! #else
!     ClogBufferLocks = malloc(NUM_CLOG_BUFFERS * sizeof(LWLockId));
!     Assert(ClogBufferLocks);
! #endif
!
!     if (!IsUnderPostmaster)
!         for (slotno = 0; slotno < NUM_CLOG_BUFFERS; slotno++)
!             ClogBufferLocks[slotno] = LWLockAssign();

      /* Init CLOG directory path */
      snprintf(ClogDir, MAXPGPATH, "%s/pg_clog", DataDir);
Index: src/backend/bootstrap/bootstrap.c
===================================================================
RCS file: /cvsroot/pgsql-server/src/backend/bootstrap/bootstrap.c,v
retrieving revision 1.150
diff -c -c -r1.150 bootstrap.c
*** src/backend/bootstrap/bootstrap.c    2 May 2003 21:59:31 -0000    1.150
--- src/backend/bootstrap/bootstrap.c    2 May 2003 22:09:28 -0000
***************
*** 301,306 ****
--- 301,311 ----

      Assert(dbName);

+     if (IsUnderPostmaster && ExecBackend && MyProc /* ordinary backend */)
+     {
+         AttachSharedMemoryAndSemaphores();
+     }
+
      if (!IsUnderPostmaster)
      {
          if (!potential_DataDir)
Index: src/backend/postmaster/postmaster.c
===================================================================
RCS file: /cvsroot/pgsql-server/src/backend/postmaster/postmaster.c,v
retrieving revision 1.319
diff -c -c -r1.319 postmaster.c
*** src/backend/postmaster/postmaster.c    2 May 2003 22:02:47 -0000    1.319
--- src/backend/postmaster/postmaster.c    2 May 2003 22:09:30 -0000
***************
*** 172,177 ****
--- 172,184 ----
  static int    ServerSock_UNIX = INVALID_SOCK;        /* stream socket server */
  #endif

+ /* Used to reduce macros tests */
+ #ifdef EXEC_BACKEND
+ const bool ExecBackend = true;
+ #else
+ const bool ExecBackend = false;
+ #endif
+
  /*
   * Set by the -o option
   */
***************
*** 1407,1413 ****
          elog(DEBUG1, "processCancelRequest: CheckPointPID in cancel request for process %d", backendPID);
          return;
      }
!
      /* See if we have a matching backend */

      for (curr = DLGetHead(BackendList); curr; curr = DLGetSucc(curr))
--- 1414,1424 ----
          elog(DEBUG1, "processCancelRequest: CheckPointPID in cancel request for process %d", backendPID);
          return;
      }
!     else if (ExecBackend)
!     {
!         AttachSharedMemoryAndSemaphores();
!     }
!
      /* See if we have a matching backend */

      for (curr = DLGetHead(BackendList); curr; curr = DLGetSucc(curr))
Index: src/backend/storage/ipc/ipci.c
===================================================================
RCS file: /cvsroot/pgsql-server/src/backend/storage/ipc/ipci.c,v
retrieving revision 1.51
diff -c -c -r1.51 ipci.c
*** src/backend/storage/ipc/ipci.c    2 May 2003 21:59:31 -0000    1.51
--- src/backend/storage/ipc/ipci.c    2 May 2003 22:09:30 -0000
***************
*** 134,136 ****
--- 134,149 ----
       */
      PMSignalInit();
  }
+
+
+ /*
+  * AttachSharedMemoryAndSemaphores
+  *        Attaches to the existing shared resources when exec()'d off
+  *        by the postmaster.
+  */
+ void
+ AttachSharedMemoryAndSemaphores(void)
+ {
+     CLOGShmemInit();
+ }
+
Index: src/backend/tcop/postgres.c
===================================================================
RCS file: /cvsroot/pgsql-server/src/backend/tcop/postgres.c,v
retrieving revision 1.329
diff -c -c -r1.329 postgres.c
*** src/backend/tcop/postgres.c    2 May 2003 21:59:31 -0000    1.329
--- src/backend/tcop/postgres.c    2 May 2003 22:09:32 -0000
***************
*** 1453,1458 ****
--- 1453,1459 ----
                  break;
          }

+
      /*
       * -d is not the same as setting
       * log_min_messages because it enables other
***************
*** 1577,1582 ****
--- 1578,1586 ----
                                   * restart... */
          }
          BaseInit();
+ #ifdef EXECBACKEND
+         AttachSharedMemoryAndSemaphores();
+ #endif
      }
      else
      {
Index: src/include/miscadmin.h
===================================================================
RCS file: /cvsroot/pgsql-server/src/include/miscadmin.h,v
retrieving revision 1.120
diff -c -c -r1.120 miscadmin.h
*** src/include/miscadmin.h    2 May 2003 21:59:31 -0000    1.120
--- src/include/miscadmin.h    2 May 2003 22:09:33 -0000
***************
*** 106,111 ****
--- 106,112 ----
   */
  extern bool IsUnderPostmaster;
  extern bool ClientAuthInProgress;
+ extern const bool ExecBackend;

  extern int    PostmasterMain(int argc, char *argv[]);
  extern void ClosePostmasterPorts(bool pgstat_too);
Index: src/include/storage/ipc.h
===================================================================
RCS file: /cvsroot/pgsql-server/src/include/storage/ipc.h,v
retrieving revision 1.59
diff -c -c -r1.59 ipc.h
*** src/include/storage/ipc.h    2 May 2003 21:59:31 -0000    1.59
--- src/include/storage/ipc.h    2 May 2003 22:09:33 -0000
***************
*** 32,36 ****
--- 32,37 ----
  extern void CreateSharedMemoryAndSemaphores(bool makePrivate,
                                  int maxBackends,
                                  int port);
+ extern void AttachSharedMemoryAndSemaphores(void);

  #endif   /* IPC_H */