Simplify and rename some GUC variables, per various recent discussions:

* stats_start_collector goes away; we always start the collector process,
unless prevented by a problem with setting up the stats UDP socket.

* stats_reset_on_server_start goes away; it seems useless in view of the
availability of pg_stat_reset().

* stats_block_level and stats_row_level are merged into a single variable
"track_counts", which controls all reports sent to the collector process.

* stats_command_string is renamed to track_activities.

* log_autovacuum is renamed to log_autovacuum_min_duration to better reflect
its meaning.

The log_autovacuum change is not a compatibility issue since it didn't exist
before 8.3 anyway.  The other changes need to be release-noted.

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 1.420 2007/09/11 00:06:42 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.421 2007/09/24 03:12:23 tgl Exp $
  *
  *--------------------------------------------------------------------
  */
@@ -736,47 +736,23 @@ static struct config_bool ConfigureNamesBool[] =
 		&Explain_pretty_print,
 		true, NULL, NULL
 	},
-	{
-		{"stats_start_collector", PGC_POSTMASTER, STATS_COLLECTOR,
-			gettext_noop("Starts the server statistics-collection subprocess."),
-			NULL
-		},
-		&pgstat_collect_startcollector,
-		true, NULL, NULL
-	},
-	{
-		{"stats_reset_on_server_start", PGC_POSTMASTER, STATS_COLLECTOR,
-			gettext_noop("Zeroes collected statistics on server restart."),
-			NULL
-		},
-		&pgstat_collect_resetonpmstart,
-		false, NULL, NULL
-	},
-	{
-		{"stats_row_level", PGC_SUSET, STATS_COLLECTOR,
-			gettext_noop("Collects row-level statistics on database activity."),
-			NULL
-		},
-		&pgstat_collect_tuplelevel,
-		true, NULL, NULL
-	},
-	{
-		{"stats_block_level", PGC_SUSET, STATS_COLLECTOR,
-			gettext_noop("Collects block-level statistics on database activity."),
-			NULL
-		},
-		&pgstat_collect_blocklevel,
-		false, NULL, NULL
-	},
 
 	{
-		{"stats_command_string", PGC_SUSET, STATS_COLLECTOR,
+		{"track_activities", PGC_SUSET, STATS_COLLECTOR,
 			gettext_noop("Collects information about executing commands."),
 			gettext_noop("Enables the collection of information on the currently "
-					"executing command of each session, along with the time "
-						 "at which that command began execution.")
+						 "executing command of each session, along with "
+						 "the time at which that command began execution.")
 		},
-		&pgstat_collect_querystring,
+		&pgstat_track_activities,
+		true, NULL, NULL
+	},
+	{
+		{"track_counts", PGC_SUSET, STATS_COLLECTOR,
+			gettext_noop("Collects statistics on database activity."),
+			NULL
+		},
+		&pgstat_track_counts,
 		true, NULL, NULL
 	},
 
@@ -1562,9 +1538,9 @@ static struct config_int ConfigureNamesInt[] =
 
 	{
 		{"log_min_duration_statement", PGC_SUSET, LOGGING_WHEN,
-			gettext_noop("Sets the minimum execution time above which statements will "
-						 "be logged."),
-			gettext_noop("Zero prints all queries. The default is -1 (turning this feature off)."),
+			gettext_noop("Sets the minimum execution time above which "
+						 "statements will be logged."),
+			gettext_noop("Zero prints all queries. -1 turns this feature off."),
 			GUC_UNIT_MS
 		},
 		&log_min_duration_statement,
@@ -1572,13 +1548,13 @@ static struct config_int ConfigureNamesInt[] =
 	},
 
 	{
-		{"log_autovacuum", PGC_SIGHUP, LOGGING_WHAT,
-			gettext_noop("Sets the minimum execution time above which autovacuum actions "
-						 "will be logged."),
-			gettext_noop("Zero prints all actions.  The default is -1 (disabling autovacuum logging)."),
+		{"log_autovacuum_min_duration", PGC_SIGHUP, LOGGING_WHAT,
+			gettext_noop("Sets the minimum execution time above which "
+						 "autovacuum actions will be logged."),
+			gettext_noop("Zero prints all actions. -1 turns autovacuum logging off."),
 			GUC_UNIT_MS
 		},
-		&Log_autovacuum,
+		&Log_autovacuum_min_duration,
 		-1, -1, INT_MAX / 1000, NULL, NULL
 	},
 

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

@@ -358,15 +358,10 @@
 
 # - Query/Index Statistics Collector -
 
-#stats_command_string = on
+#track_activities = on
+#track_counts = on
 #update_process_title = on
 
-#stats_start_collector = on		# needed for block or row stats
-					# (change requires restart)
-#stats_block_level = off
-#stats_row_level = on
-#stats_reset_on_server_start = off	# (change requires restart)
-
 
 # - Statistics Monitoring -
 
@@ -381,13 +376,13 @@
 #---------------------------------------------------------------------------
 
 #autovacuum = on			# enable autovacuum subprocess?
-					# 'on' requires stats_start_collector
-					# and stats_row_level to also be on
-#autovacuum_max_workers = 3		# max # of autovacuum subprocesses
-#autovacuum_naptime = 1min		# time between autovacuum runs
-#log_autovacuum = -1			# -1 is disabled, 0 logs all actions
+					# 'on' requires track_counts
+					# to also be on
+#log_autovacuum_min_duration = -1	# -1 disables, 0 logs all actions
 					# and their durations, > 0 logs only
 					# actions running at least N msec.
+#autovacuum_max_workers = 3		# max # of autovacuum subprocesses
+#autovacuum_naptime = 1min		# time between autovacuum runs
 #autovacuum_vacuum_threshold = 50	# min # of tuple updates before
 					# vacuum
 #autovacuum_analyze_threshold = 50	# min # of tuple updates before