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Re: Persistent connections to database?



Joshua D. Drake wrote:
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On Fri, 16 Nov 2007 18:49:59 -0600
Charley Tiggs <..hidden..> wrote:

Joshua D. Drake wrote:
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On Fri, 16 Nov 2007 18:15:27 -0600
Charley Tiggs <..hidden..> wrote:

Joshua D. Drake wrote:
It sounds more like a machine level issue (bad configuration of
postgresql, not enough IO/RAM etc..)
Josh,
How many connections are we talking about at peak? What type of
hardware do you have?
80 connections at peak. Before the past two days, it had rarely exceeded 20 connections at peak.

Dell PowerEdge 860, dual-core Xeon 3.2 GHz, with 2 gig of memory.
72GB SCSI hard drives with 1MB disc cache.
How many hard drives, what raid level? I assume you mean 1G of
cache?

What does your postgreql.conf look like? Is this a dedicated
postgresql machine or does apache and ledgersmb run on top of it?

What does it say if you connect to template1 and run vacuum verbose
analyze (I need the last 5 lines).
OS is FreeBSD 6.2. 2 hard drives RAID 0 (I think.  I can't remember
for sure).  I do mean 1MB HDD cache.  I looked for the smallest one
possible.

Dedicated db machine, nothing else running on it.

Vaccum:

INFO:  analyzing "pg_catalog.pg_auth_members"
INFO:  "pg_auth_members": scanned 0 of 0 pages, containing 0 live
rows and 0 dead rows; 0 rows in sample, 0 estimated total rows
INFO:  free space map contains 13637 pages in 649 relations
DETAIL:  A total of 21168 page slots are in use (including overhead).
21168 page slots are required to track all free space.
Current limits are:  179200 page slots, 1000 relations, using 1115 kB.

Bingo :)...

increase your max_fsm_pages to 250000

What about the rest of your conf (please attach)... shared_memory,
work_mem, fsync, wal_sync_method etc...

conf attached...

Could you comment on why I need to increase the free space map pages? I'm going to do it. I'm just trying to understand why I'm doing it.

Charley

#---------------------------------------------------------------------------
# FILE LOCATIONS
#---------------------------------------------------------------------------

# The default values of these variables are driven from the -D command line
# switch or PGDATA environment variable, represented here as ConfigDir.

#data_directory = 'ConfigDir'		# use data in another directory
					# (change requires restart)
#hba_file = 'ConfigDir/pg_hba.conf'	# host-based authentication file
					# (change requires restart)
#ident_file = 'ConfigDir/pg_ident.conf'	# ident configuration file
					# (change requires restart)

# If external_pid_file is not explicitly set, no extra PID file is written.
#external_pid_file = '(none)'		# write an extra PID file
					# (change requires restart)


#---------------------------------------------------------------------------
# CONNECTIONS AND AUTHENTICATION
#---------------------------------------------------------------------------

# - Connection Settings -

listen_addresses = '216.168.61.246'	# what IP address(es) to listen on; 
					# comma-separated list of addresses;
					# defaults to 'localhost', '*' = all
					# (change requires restart)
#port = 5432				# (change requires restart)
max_connections = 40			# (change requires restart)
# Note: increasing max_connections costs ~400 bytes of shared memory per 
# connection slot, plus lock space (see max_locks_per_transaction).  You
# might also need to raise shared_buffers to support more connections.
#superuser_reserved_connections = 3	# (change requires restart)
#unix_socket_directory = ''		# (change requires restart)
#unix_socket_group = ''			# (change requires restart)
#unix_socket_permissions = 0777		# octal
					# (change requires restart)
#bonjour_name = ''			# defaults to the computer name
					# (change requires restart)

# - Security & Authentication -

#authentication_timeout = 1min		# 1s-600s
#ssl = off				# (change requires restart)
#password_encryption = on
#db_user_namespace = off

# Kerberos
#krb_server_keyfile = ''		# (change requires restart)
#krb_srvname = 'postgres'		# (change requires restart)
#krb_server_hostname = ''		# empty string matches any keytab entry
					# (change requires restart)
#krb_caseins_users = off		# (change requires restart)

# - TCP Keepalives -
# see 'man 7 tcp' for details

#tcp_keepalives_idle = 0		# TCP_KEEPIDLE, in seconds;
					# 0 selects the system default
#tcp_keepalives_interval = 0		# TCP_KEEPINTVL, in seconds;
					# 0 selects the system default
#tcp_keepalives_count = 0		# TCP_KEEPCNT;
					# 0 selects the system default


#---------------------------------------------------------------------------
# RESOURCE USAGE (except WAL)
#---------------------------------------------------------------------------

# - Memory -

shared_buffers = 32MB			# min 128kB or max_connections*16kB
					# (change requires restart)
#temp_buffers = 8MB			# min 800kB
#max_prepared_transactions = 5		# can be 0 or more
					# (change requires restart)
# Note: increasing max_prepared_transactions costs ~600 bytes of shared memory
# per transaction slot, plus lock space (see max_locks_per_transaction).
work_mem = 4MB				# min 64kB
maintenance_work_mem = 256MB		# min 1MB
#max_stack_depth = 2MB			# min 100kB

# - Free Space Map -

max_fsm_pages = 179200		# min max_fsm_relations*16, 6 bytes each
					# (change requires restart)
#max_fsm_relations = 1000		# min 100, ~70 bytes each
					# (change requires restart)

# - Kernel Resource Usage -

#max_files_per_process = 1000		# min 25
					# (change requires restart)
#shared_preload_libraries = ''		# (change requires restart)

# - 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 = 200ms			# 10-10000ms between rounds
#bgwriter_lru_percent = 1.0		# 0-100% of LRU buffers scanned/round
#bgwriter_lru_maxpages = 5		# 0-1000 buffers max written/round
#bgwriter_all_percent = 0.333		# 0-100% of all buffers scanned/round
#bgwriter_all_maxpages = 5		# 0-1000 buffers max written/round


#---------------------------------------------------------------------------
# WRITE AHEAD LOG
#---------------------------------------------------------------------------

# - Settings -

#fsync = on				# turns forced synchronization on or off
#wal_sync_method = fsync		# the default is the first option 
					# supported by the operating system:
					#   open_datasync
					#   fdatasync
					#   fsync
					#   fsync_writethrough
					#   open_sync
#full_page_writes = on			# recover from partial page writes
#wal_buffers = 64kB			# min 32kB
					# (change requires restart)
#commit_delay = 0			# range 0-100000, in microseconds
#commit_siblings = 5			# range 1-1000

# - Checkpoints -

checkpoint_segments = 12		# in logfile segments, min 1, 16MB each
#checkpoint_timeout = 5min		# range 30s-1h
#checkpoint_warning = 30s		# 0 is off

# - Archiving -

#archive_command = ''		# command to use to archive a logfile segment
#archive_timeout = 0		# force a logfile segment switch after this
				# many seconds; 0 is off


#---------------------------------------------------------------------------
# QUERY TUNING
#---------------------------------------------------------------------------

# - Planner Method Configuration -

#enable_bitmapscan = on
#enable_hashagg = on
#enable_hashjoin = on
#enable_indexscan = on
#enable_mergejoin = on
#enable_nestloop = on
#enable_seqscan = on
#enable_sort = on
#enable_tidscan = on

# - Planner Cost Constants -

#seq_page_cost = 1.0			# measured on an arbitrary scale
random_page_cost = 2.0			# same scale as above
#cpu_tuple_cost = 0.01			# same scale as above
#cpu_index_tuple_cost = 0.005		# same scale as above
#cpu_operator_cost = 0.0025		# same scale as above
effective_cache_size = 512MB

# - Genetic Query Optimizer -

#geqo = on
#geqo_threshold = 12
#geqo_effort = 5			# range 1-10
#geqo_pool_size = 0			# selects default based on effort
#geqo_generations = 0			# selects default based on effort
#geqo_selection_bias = 2.0		# range 1.5-2.0

# - Other Planner Options -

#default_statistics_target = 10		# range 1-1000
#constraint_exclusion = off
#from_collapse_limit = 8
#join_collapse_limit = 8		# 1 disables collapsing of explicit 
					# JOINs


#---------------------------------------------------------------------------
# ERROR REPORTING AND LOGGING
#---------------------------------------------------------------------------

# - Where to Log -

#log_destination = 'syslog'
log_destination = 'stderr'		# Valid values are combinations of 
					# stderr, syslog and eventlog, 
					# depending on platform.

# This is used when logging to stderr:
redirect_stderr = on			# Enable capturing of stderr into log 
					# files
					# (change requires restart)

# These are only used if redirect_stderr is on:
log_directory = '/var/log/pgsql'		# Directory where log files are written
					# Can be absolute or relative to PGDATA
log_filename = '%Y-%m-%d_%H%M%S.log' # Log file name pattern.
					# Can include strftime() escapes
#log_truncate_on_rotation = off # If on, any existing log file of the same 
					# name as the new log file will be
					# truncated rather than appended to. But
					# such truncation only occurs on
					# time-driven rotation, not on restarts
					# or size-driven rotation. Default is
					# off, meaning append to existing files
					# in all cases.
log_rotation_age = 1d			# Automatic rotation of logfiles will 
					# happen after that time.  0 to 
					# disable.
log_rotation_size = 10MB		# Automatic rotation of logfiles will 
					# happen after that much log
					# output.  0 to disable.

# These are relevant when logging to syslog:
#syslog_facility = 'LOCAL0'
#syslog_ident = 'postgres'


# - When to Log -

#client_min_messages = notice		# Values, in order of decreasing detail:
					#   debug5
					#   debug4
					#   debug3
					#   debug2
					#   debug1
					#   log
					#   notice
					#   warning
					#   error

log_min_messages = warning		# Values, in order of decreasing detail:
					#   debug5
					#   debug4
					#   debug3
					#   debug2
					#   debug1
					#   info
					#   notice
					#   warning
					#   error
					#   log
					#   fatal
					#   panic

log_error_verbosity = default		# terse, default, or verbose messages

log_min_error_statement = error	# Values in order of increasing severity:
				 	#   debug5
					#   debug4
					#   debug3
					#   debug2
					#   debug1
				 	#   info
					#   notice
					#   warning
					#   error
					#   fatal
					#   panic (effectively off)

#log_min_duration_statement = -1	# -1 is disabled, 0 logs all statements
					# and their durations.

silent_mode = on
#silent_mode = off			# DO NOT USE without syslog or 
					# redirect_stderr
					# (change requires restart)

# - What to Log -

#debug_print_parse = off
#debug_print_rewritten = off
#debug_print_plan = off
#debug_pretty_print = off
#log_connections = off
#log_disconnections = off
#log_duration = off
log_line_prefix = '%t - %u - %r: '	# Special values:
					#   %u = user name
					#   %d = database name
					#   %r = remote host and port
					#   %h = remote host
					#   %p = PID
					#   %t = timestamp (no milliseconds)
					#   %m = timestamp with milliseconds
					#   %i = command tag
					#   %c = session id
					#   %l = session line number
					#   %s = session start timestamp
					#   %x = transaction id
					#   %q = stop here in non-session 
					#        processes
					#   %% = '%'
					# e.g. '<%u%%%d> '
log_statement = 'none'			# none, ddl, mod, all
#log_hostname = off


#---------------------------------------------------------------------------
# RUNTIME STATISTICS
#---------------------------------------------------------------------------

# - Query/Index Statistics Collector -

#stats_command_string = 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 -

#log_parser_stats = off
#log_planner_stats = off
#log_executor_stats = off
#log_statement_stats = off


#---------------------------------------------------------------------------
# AUTOVACUUM PARAMETERS
#---------------------------------------------------------------------------

autovacuum = on

#autovacuum = off			# enable autovacuum subprocess?
					# 'on' requires stats_start_collector
					# and stats_row_level to also be on
autovacuum_naptime = 20min		# time between autovacuum runs
autovacuum_vacuum_threshold = 500	# min # of tuple updates before
					# vacuum
autovacuum_analyze_threshold = 250	# min # of tuple updates before 
					# analyze
autovacuum_vacuum_scale_factor = 0.2	# fraction of rel size before 
					# vacuum
#autovacuum_analyze_scale_factor = 0.1	# fraction of rel size before 
					# analyze
#autovacuum_freeze_max_age = 200000000	# maximum XID age before forced vacuum
					# (change requires restart)
#autovacuum_vacuum_cost_delay = -1	# default vacuum cost delay for 
					# autovacuum, -1 means use 
					# vacuum_cost_delay
#autovacuum_vacuum_cost_limit = -1	# default vacuum cost limit for 
					# autovacuum, -1 means use
					# vacuum_cost_limit


#---------------------------------------------------------------------------
# CLIENT CONNECTION DEFAULTS
#---------------------------------------------------------------------------

# - Statement Behavior -

#search_path = '"$user",public'		# schema names
#default_tablespace = ''		# a tablespace name, '' uses
					# the default
#check_function_bodies = on
#default_transaction_isolation = 'read committed'
#default_transaction_read_only = off
#statement_timeout = 0			# 0 is disabled
#vacuum_freeze_min_age = 100000000

# - Locale and Formatting -

datestyle = 'iso, mdy'
#timezone = unknown			# actually, defaults to TZ 
					# environment setting
#timezone_abbreviations = 'Default'     # select the set of available timezone
					# abbreviations. Currently, there are
					#   Default
					#   Australia
					#   India
					# However you can also create your own
					# file in share/timezonesets/.
#extra_float_digits = 0			# min -15, max 2
#client_encoding = sql_ascii		# actually, defaults to database
					# encoding

# These settings are initialized by initdb -- they might be changed
lc_messages = 'C'			# locale for system error message 
					# strings
lc_monetary = 'C'			# locale for monetary formatting
lc_numeric = 'C'			# locale for number formatting
lc_time = 'C'				# locale for time formatting

# - Other Defaults -

#explain_pretty_print = on
#dynamic_library_path = '$libdir'
#local_preload_libraries = ''


#---------------------------------------------------------------------------
# LOCK MANAGEMENT
#---------------------------------------------------------------------------

#deadlock_timeout = 1s
#max_locks_per_transaction = 64		# min 10
					# (change requires restart)
# Note: each lock table slot uses ~270 bytes of shared memory, and there are
# max_locks_per_transaction * (max_connections + max_prepared_transactions)
# lock table slots.


#---------------------------------------------------------------------------
# VERSION/PLATFORM COMPATIBILITY
#---------------------------------------------------------------------------

# - Previous Postgres Versions -

#add_missing_from = off
#array_nulls = on
#backslash_quote = safe_encoding	# on, off, or safe_encoding
default_with_oids = off
#escape_string_warning = on
#standard_conforming_strings = off
#regex_flavor = advanced		# advanced, extended, or basic
#sql_inheritance = on

# - Other Platforms & Clients -

#transform_null_equals = off


#---------------------------------------------------------------------------
# CUSTOMIZED OPTIONS
#---------------------------------------------------------------------------

#custom_variable_classes = ''		# list of custom variable class names