Enable autovacuum in the default configuration, per discussion.

doc/src/sgml/config.sgml

-<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.101 2007/01/09 22:16:46 momjian Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.102 2007/01/16 18:26:02 alvherre Exp $ -->
 
 <chapter Id="runtime-config">
   <title>Server Configuration</title>
@@ -3043,7 +3043,8 @@ SELECT * FROM parent WHERE key = 2400;
       <listitem>
        <para>
         Enables the collection of row-level statistics on database
-        activity. This parameter is off by default.
+        activity. This parameter is on by default, because the autovacuum
+        daemon needs the collected information.
         Only superusers can change this setting.
        </para>
       </listitem>

doc/src/sgml/maintenance.sgml

-<!-- $PostgreSQL: pgsql/doc/src/sgml/maintenance.sgml,v 1.65 2006/12/27 14:55:17 momjian Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/maintenance.sgml,v 1.66 2007/01/16 18:26:02 alvherre Exp $ -->
 
 <chapter id="maintenance">
  <title>Routine Database Maintenance Tasks</title>
@@ -477,7 +477,9 @@ HINT:  Stop the postmaster and use a standalone backend to VACUUM in "mydb".
     linkend="guc-stats-start-collector"> and <xref
     linkend="guc-stats-row-level"> are set to <literal>true</literal>.  Also,
     it's important to allow a slot for the autovacuum process when choosing
-    the value of <xref linkend="guc-superuser-reserved-connections">.
+    the value of <xref linkend="guc-superuser-reserved-connections">.  In
+    the default configuration, autovacuuming is enabled and the related
+    configuration parameters are appropriately set.
    </para>
 
    <para>

src/backend/utils/misc/guc.c

@@ -10,7 +10,7 @@
  * Written by Peter Eisentraut <peter_e@gmx.net>.
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.367 2007/01/09 22:16:46 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.368 2007/01/16 18:26:02 alvherre Exp $
  *
  *--------------------------------------------------------------------
  */
@@ -711,7 +711,7 @@ static struct config_bool ConfigureNamesBool[] =
 			NULL
 		},
 		&pgstat_collect_tuplelevel,
-		false, NULL, NULL
+		true, NULL, NULL
 	},
 	{
 		{"stats_block_level", PGC_SUSET, STATS_COLLECTOR,
@@ -748,7 +748,7 @@ static struct config_bool ConfigureNamesBool[] =
 			NULL
 		},
 		&autovacuum_start_daemon,
-		false, NULL, NULL
+		true, NULL, NULL
 	},
 
 	{

src/backend/utils/misc/postgresql.conf.sample

@@ -349,7 +349,7 @@
 #stats_start_collector = on		# needed for block or row stats
 					# (change requires restart)
 #stats_block_level = off
-#stats_row_level = off
+#stats_row_level = on
 #stats_reset_on_server_start = off	# (change requires restart)
 
 
@@ -365,7 +365,7 @@
 # AUTOVACUUM PARAMETERS
 #---------------------------------------------------------------------------
 
-#autovacuum = off			# enable autovacuum subprocess?
+#autovacuum = on			# enable autovacuum subprocess?
 					# 'on' requires stats_start_collector
 					# and stats_row_level to also be on
 #autovacuum_naptime = 1min		# time between autovacuum runs