Make autovacuum behavior more agressive, per discussion on hackers list

--- was part of autovacuum default 'on' patch that was reverted, but we
want this part.

Peter Eisentraut

doc/src/sgml/config.sgml

-<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.81 2006/09/02 23:04:20 momjian Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.82 2006/09/02 23:12:16 momjian Exp $ -->
 
 <chapter Id="runtime-config">
   <title>Server Configuration</title>
@@ -3113,7 +3113,7 @@ SELECT * FROM parent WHERE key = 2400;
        <para>
         Specifies the minimum number of updated or deleted tuples needed
         to trigger a <command>VACUUM</> in any one table.
-        The default is 1000.
+        The default is 500.
         This parameter can only be set in the <filename>postgresql.conf</>
         file or on the server command line.
         This setting can be overridden for individual tables by entries in
@@ -3131,7 +3131,7 @@ SELECT * FROM parent WHERE key = 2400;
        <para>
         Specifies the minimum number of inserted, updated or deleted tuples
         needed to trigger an <command>ANALYZE</> in any one table.
-        The default is 500.
+        The default is 250.
         This parameter can only be set in the <filename>postgresql.conf</>
         file or on the server command line.
         This setting can be overridden for individual tables by entries in
@@ -3150,7 +3150,7 @@ SELECT * FROM parent WHERE key = 2400;
         Specifies a fraction of the table size to add to
         <varname>autovacuum_vacuum_threshold</varname>
         when deciding whether to trigger a <command>VACUUM</>.
-        The default is 0.4.
+        The default is 0.2.
         This parameter can only be set in the <filename>postgresql.conf</>
         file or on the server command line.
         This setting can be overridden for individual tables by entries in
@@ -3169,7 +3169,7 @@ SELECT * FROM parent WHERE key = 2400;
         Specifies a fraction of the table size to add to
         <varname>autovacuum_analyze_threshold</varname>
         when deciding whether to trigger an <command>ANALYZE</>.
-        The default is 0.2.
+        The default is 0.1.
         This parameter can only be set in the <filename>postgresql.conf</>
         file or on the server command line.
         This setting can be overridden for individual tables by entries in

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 1.349 2006/09/02 23:04:20 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.350 2006/09/02 23:12:16 momjian Exp $
  *
  *--------------------------------------------------------------------
  */
@@ -1564,7 +1564,7 @@ static struct config_int ConfigureNamesInt[] =
 			NULL
 		},
 		&autovacuum_vac_thresh,
-		1000, 0, INT_MAX, NULL, NULL
+		500, 0, INT_MAX, NULL, NULL
 	},
 	{
 		{"autovacuum_analyze_threshold", PGC_SIGHUP, AUTOVACUUM,
@@ -1572,7 +1572,7 @@ static struct config_int ConfigureNamesInt[] =
 			NULL
 		},
 		&autovacuum_anl_thresh,
-		500, 0, INT_MAX, NULL, NULL
+		250, 0, INT_MAX, NULL, NULL
 	},
 
 	{
@@ -1738,7 +1738,7 @@ static struct config_real ConfigureNamesReal[] =
 			NULL
 		},
 		&autovacuum_vac_scale,
-		0.4, 0.0, 100.0, NULL, NULL
+		0.2, 0.0, 100.0, NULL, NULL
 	},
 	{
 		{"autovacuum_analyze_scale_factor", PGC_SIGHUP, AUTOVACUUM,
@@ -1746,7 +1746,7 @@ static struct config_real ConfigureNamesReal[] =
 			NULL
 		},
 		&autovacuum_anl_scale,
-		0.2, 0.0, 100.0, NULL, NULL
+		0.1, 0.0, 100.0, NULL, NULL
 	},
 
 	/* End-of-list marker */

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

@@ -363,13 +363,13 @@
 
 #autovacuum = off			# enable autovacuum subprocess?
 #autovacuum_naptime = 60		# time between autovacuum runs, in secs
-#autovacuum_vacuum_threshold = 1000	# min # of tuple updates before
+#autovacuum_vacuum_threshold = 500	# min # of tuple updates before
 					# vacuum
-#autovacuum_analyze_threshold = 500	# min # of tuple updates before 
+#autovacuum_analyze_threshold = 250	# min # of tuple updates before 
 					# analyze
-#autovacuum_vacuum_scale_factor = 0.4	# fraction of rel size before 
+#autovacuum_vacuum_scale_factor = 0.2	# fraction of rel size before 
 					# vacuum
-#autovacuum_analyze_scale_factor = 0.2	# fraction of rel size before 
+#autovacuum_analyze_scale_factor = 0.1	# fraction of rel size before 
 					# analyze
 #autovacuum_vacuum_cost_delay = -1	# default vacuum cost delay for 
 					# autovac, -1 means use