Index: doc/src/sgml/runtime.sgml
===================================================================
RCS file: /cvsroot/pgsql-server/doc/src/sgml/runtime.sgml,v
retrieving revision 1.135
diff -c -c -r1.135 runtime.sgml
*** doc/src/sgml/runtime.sgml	2 Sep 2002 13:45:30 -0000	1.135
--- doc/src/sgml/runtime.sgml	7 Sep 2002 04:37:06 -0000
***************
*** 2017,2022 ****
--- 2017,2034 ----
        </listitem>
       </varlistentry>
  
+     <variablelist>
+      <varlistentry>
+       <term><varname>CHECKPOINT_WARNING</varname> (<type>integer</type>)</term>
+       <listitem>
+        <para>
+         Send a message to the server logs if checkpoints caused by the
+         filling of checkpoint segment files happens more frequently than
+         this number of seconds.  Zero turns off the warning.
+        </para>
+       </listitem>
+      </varlistentry>
+ 
       <varlistentry>
        <term><varname>COMMIT_DELAY</varname> (<type>integer</type>)</term>
        <listitem>
Index: doc/src/sgml/wal.sgml
===================================================================
RCS file: /cvsroot/pgsql-server/doc/src/sgml/wal.sgml,v
retrieving revision 1.20
diff -c -c -r1.20 wal.sgml
*** doc/src/sgml/wal.sgml	6 Sep 2002 20:26:00 -0000	1.20
--- doc/src/sgml/wal.sgml	7 Sep 2002 04:37:08 -0000
***************
*** 314,319 ****
--- 314,329 ----
    </para>
  
    <para>
+    Checkpoints are fairly expensive because they force all dirty kernel
+    buffers to disk using the operating system <literal>sync()</> call.
+    Busy servers may fill checkpoint segment files too quickly,
+    causing excessive checkpointing. If such forced checkpoints happen
+    more than <varname>CHECKPOINT_WARNING</varname> seconds, a message
+    will be output to the server logs recommending increasing 
+    <varname>CHECKPOINT_SEGMENTS</varname>.
+   </para>
+ 
+   <para>
     The <varname>COMMIT_DELAY</varname> parameter defines for how many
     microseconds the backend will sleep after writing a commit
     record to the log with <function>LogInsert</function> but before
Index: src/backend/postmaster/postmaster.c
===================================================================
RCS file: /cvsroot/pgsql-server/src/backend/postmaster/postmaster.c,v
retrieving revision 1.288
diff -c -c -r1.288 postmaster.c
*** src/backend/postmaster/postmaster.c	4 Sep 2002 20:31:24 -0000	1.288
--- src/backend/postmaster/postmaster.c	7 Sep 2002 04:37:34 -0000
***************
*** 198,203 ****
--- 198,205 ----
  int			PreAuthDelay = 0;
  int			AuthenticationTimeout = 60;
  int			CheckPointTimeout = 300;
+ int			CheckPointWarning = 30;
+ time_t		LastSignalledCheckpoint = 0;
  
  bool		HostnameLookup;		/* for ps display */
  bool		ShowPortNumber;
***************
*** 2316,2321 ****
--- 2318,2339 ----
  
  	if (CheckPostmasterSignal(PMSIGNAL_DO_CHECKPOINT))
  	{
+ 		if (CheckPointWarning != 0)
+ 		{
+ 			/*
+ 			 *	This only times checkpoints forced by running out of
+ 			 *	segment files.  Other checkpoints could reduce
+ 			 *	the frequency of forced checkpoints.
+ 			 */
+ 			time_t now = time(NULL);
+ 
+ 			if (now - LastSignalledCheckpoint < CheckPointWarning)
+ 				elog(LOG, "Checkpoint segments are being created too frequently (%d secs)\n
+ 				Consider increasing CHECKPOINT_SEGMENTS",
+ 				now - LastSignalledCheckpoint);
+ 			LastSignalledCheckpoint = now;
+ 		}
+ 
  		/*
  		 * Request to schedule a checkpoint
  		 *
Index: src/backend/utils/misc/guc.c
===================================================================
RCS file: /cvsroot/pgsql-server/src/backend/utils/misc/guc.c,v
retrieving revision 1.93
diff -c -c -r1.93 guc.c
*** src/backend/utils/misc/guc.c	4 Sep 2002 20:31:33 -0000	1.93
--- src/backend/utils/misc/guc.c	7 Sep 2002 04:37:44 -0000
***************
*** 662,667 ****
--- 662,672 ----
  	},
  
  	{
+ 		{"checkpoint_warning", PGC_SIGHUP}, &CheckPointWarning,
+ 		30, 0, INT_MAX, NULL, NULL
+ 	},
+ 
+ 	{
  		{"wal_buffers", PGC_POSTMASTER}, &XLOGbuffers,
  		8, 4, INT_MAX, NULL, NULL
  	},
Index: src/backend/utils/misc/postgresql.conf.sample
===================================================================
RCS file: /cvsroot/pgsql-server/src/backend/utils/misc/postgresql.conf.sample,v
retrieving revision 1.52
diff -c -c -r1.52 postgresql.conf.sample
*** src/backend/utils/misc/postgresql.conf.sample	2 Sep 2002 05:42:54 -0000	1.52
--- src/backend/utils/misc/postgresql.conf.sample	7 Sep 2002 04:37:45 -0000
***************
*** 67,72 ****
--- 67,73 ----
  #
  #checkpoint_segments = 3	# in logfile segments, min 1, 16MB each
  #checkpoint_timeout = 300	# range 30-3600, in seconds
+ #checkpoint_warning = 30	# 0 is off, in seconds
  #
  #commit_delay = 0		# range 0-100000, in microseconds
  #commit_siblings = 5		# range 1-1000
Index: src/include/access/xlog.h
===================================================================
RCS file: /cvsroot/pgsql-server/src/include/access/xlog.h,v
retrieving revision 1.37
diff -c -c -r1.37 xlog.h
*** src/include/access/xlog.h	4 Sep 2002 20:31:37 -0000	1.37
--- src/include/access/xlog.h	7 Sep 2002 04:37:47 -0000
***************
*** 184,189 ****
--- 184,190 ----
  
  /* these variables are GUC parameters related to XLOG */
  extern int	CheckPointSegments;
+ extern int	CheckPointWarning;
  extern int	XLOGbuffers;
  extern int	XLOG_DEBUG;
  extern char *XLOG_sync_method;