Add code to dump contents of free space map into $PGDATA/global/pg_fsm.cache

at database shutdown, and then load it again at database startup.  This
preserves our hard-won knowledge of free space across restarts (given
an orderly shutdown, that is).

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 1.147 2002/12/15 16:17:38 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/bootstrap/bootstrap.c,v 1.148 2003/03/06 00:04:27 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -34,6 +34,7 @@
 #include "executor/executor.h"
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
+#include "storage/freespace.h"
 #include "storage/ipc.h"
 #include "storage/proc.h"
 #include "tcop/tcopprot.h"
@@ -398,10 +399,12 @@ BootstrapMain(int argc, char *argv[])
 
 		case BS_XLOG_STARTUP:
 			StartupXLOG();
+			LoadFreeSpaceMap();
 			proc_exit(0);		/* done */
 
 		case BS_XLOG_SHUTDOWN:
 			ShutdownXLOG();
+			DumpFreeSpaceMap();
 			proc_exit(0);		/* done */
 
 		default:

src/backend/tcop/postgres.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/tcop/postgres.c,v 1.315 2003/02/10 04:44:46 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/tcop/postgres.c,v 1.316 2003/03/06 00:04:27 tgl Exp $
  *
  * NOTES
  *	  this is the "main" module of the postgres backend and
@@ -46,6 +46,7 @@
 #include "parser/analyze.h"
 #include "parser/parser.h"
 #include "rewrite/rewriteHandler.h"
+#include "storage/freespace.h"
 #include "storage/ipc.h"
 #include "storage/proc.h"
 #include "tcop/fastpath.h"
@@ -1740,6 +1741,13 @@ PostgresMain(int argc, char *argv[], const char *username)
 		 */
 		StartupXLOG();
 		on_shmem_exit(ShutdownXLOG, 0);
+
+		/*
+		 * Read any existing FSM cache file, and register to write one out
+		 * at exit.
+		 */
+		LoadFreeSpaceMap();
+		on_shmem_exit(DumpFreeSpaceMap, 0);
 	}
 
 	/*
@@ -1781,7 +1789,7 @@ PostgresMain(int argc, char *argv[], const char *username)
 	if (!IsUnderPostmaster)
 	{
 		puts("\nPOSTGRES backend interactive interface ");
-		puts("$Revision: 1.315 $ $Date: 2003/02/10 04:44:46 $\n");
+		puts("$Revision: 1.316 $ $Date: 2003/03/06 00:04:27 $\n");
 	}
 
 	/*

src/include/storage/freespace.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: freespace.h,v 1.9 2003/03/04 21:51:22 tgl Exp $
+ * $Id: freespace.h,v 1.10 2003/03/06 00:04:27 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -60,6 +60,9 @@ extern void FreeSpaceMapForgetDatabase(Oid dbid);
 
 extern void PrintFreeSpaceMapStatistics(int elevel);
 
+extern void DumpFreeSpaceMap(void);
+extern void LoadFreeSpaceMap(void);
+
 #ifdef FREESPACE_DEBUG
 extern void DumpFreeSpace(void);
 #endif