Document background writer control parameters, do some editorial work

on other recent changes in runtime parameter list.

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

@@ -70,17 +70,6 @@
 #maintenance_work_mem = 16384	# min 1024, size in KB
 #max_stack_depth = 2048		# min 100, size in KB
 
-#vacuum_cost_page_hit = 1	# 0-10000 credits
-#vacuum_cost_page_miss = 10	# 0-10000 credits
-#vacuum_cost_page_dirty = 20	# 0-10000 credits
-#vacuum_cost_limit = 200	# 0-10000 credits
-#vacuum_cost_delay = 0		# 0-1000 milliseconds
-
-# - Background writer -
-#bgwriter_delay = 200		# 10-5000 milliseconds
-#bgwriter_percent = 1		# 0-100% of dirty buffers
-#bgwriter_maxpages = 100	# 1-1000 buffers max at once
-
 # - Free Space Map -
 
 #max_fsm_pages = 20000		# min max_fsm_relations*16, 6 bytes each
@@ -91,6 +80,20 @@
 #max_files_per_process = 1000	# min 25
 #preload_libraries = ''
 
+# - Cost-Based Vacuum Delay -
+
+#vacuum_cost_delay = 0		# 0-1000 milliseconds
+#vacuum_cost_page_hit = 1	# 0-10000 credits
+#vacuum_cost_page_miss = 10	# 0-10000 credits
+#vacuum_cost_page_dirty = 20	# 0-10000 credits
+#vacuum_cost_limit = 200	# 0-10000 credits
+
+# - Background writer -
+
+#bgwriter_delay = 200		# 10-5000 milliseconds
+#bgwriter_percent = 1		# 1-100% of dirty buffers
+#bgwriter_maxpages = 100	# 1-1000 buffers max at once
+
 
 #---------------------------------------------------------------------------
 # WRITE AHEAD LOG
@@ -102,14 +105,14 @@
 #wal_sync_method = fsync	# the default varies across platforms:
 				# fsync, fdatasync, open_sync, or open_datasync
 #wal_buffers = 8		# min 4, 8KB each
+#commit_delay = 0		# range 0-100000, in microseconds
+#commit_siblings = 5		# range 1-1000
 
 # - Checkpoints -
 
 #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
 
 # - Archiving -
 
@@ -206,7 +209,7 @@
 				 
 #log_min_duration_statement = -1 # -1 is disabled, in milliseconds.
 
-#silent_mode = false		 # DO NOT USE without Syslog!
+#silent_mode = false		 # DO NOT USE without syslog or redirect_stderr
 
 # - What to Log -
 
@@ -240,8 +243,6 @@
 #log_executor_stats = false
 #log_statement_stats = false
 
-#debug_shared_buffers = 0	# 0-600 seconds
-
 # - Query/Index Statistics Collector -
 
 #stats_start_collector = true