Re: the right time to vacuum database?

On 6 5 ,   9 25 , a...@crankycanuck.ca (Andrew Sullivan) wrote:
> On Tue, Jun 05, 2007 at 03:33:09AM -0700, Charles.Hou wrote:
> > how can i know that it's the time to vacuumdb? i set the crontab to
> > vacuumdb 3 times in one day. because my database size increase from
> > 440MB to 460MB in 8 hours.
>
> You haven't told us enough.  What's the churn on the database, to
> begin with?  That's only 20M.  If you replace approximately 20M in 8
> hours, then it might be that the FSM is working perfectly, and this
> is the overhead that is reasonable to keep around to allow your
> database to work perfectly.
>
> Also, have you looked into autovacuum?  It might take some of the
> guesswork out of this.
>
> Finally, I expect that most of your churn is in particular tables.
> Those are the ones you want to vacuum frequently.  The rest of them
> aren't that interesting.  The way to learn about this is to use
> VACUUM VERBOSE, which will give you information about how many pages
> it is recovering.
>
> A
>
> --
> Andrew Sullivan  | a...@crankycanuck.ca
> "The year's penultimate month" is not in truth a good way of saying
> November.
>                 --H.W. Fowler
>
> ---------------------------(end of broadcast)---------------------------
> TIP 2: Don't 'kill -9' the postmaster

the version of PostgreSQL is 8.1.3 on i686-redhat-linux-gnu,compiled
by GCC 3.4.4 (Red-Hat 3.4.4-2)
Client connected: about 100 pc, 1 pc with 1 connection at least, the
max is 4 connections
194 tables on the database, and some of the tables  always executed
the update/insert command .
i also set the autovacuum to enable. today, the database size is
497MB. 497-440MB=57MB, 57 MB have been increased in 18  hours.
what's wrong with my PostgreSql Server?
postgresql.conf

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

# - Connection Settings -

#listen_addresses = 'localhost'        # what IP address(es) to listen on;
listen_addresses = '*'            # what IP address(es) to listen on;
                    # comma-separated list of addresses;
                    # defaults to 'localhost', '*' = all
#port = 5432
max_connections = 1000
# 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 = 2
#unix_socket_directory = ''
#unix_socket_group = ''
#unix_socket_permissions = 0777        # octal
#bonjour_name = ''            # defaults to the computer name

# - Security & Authentication -

#authentication_timeout = 60        # 1-600, in seconds
#ssl = off
#password_encryption = on
#db_user_namespace = off

# Kerberos
#krb_server_keyfile = ''
#krb_srvname = 'postgres'
#krb_server_hostname = ''        # empty string matches any keytab entry
#krb_caseins_users = off

# - 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 = 2000            # min 16 or max_connections*2, 8KB each
temp_buffers = 1000            # min 100, 8KB each
#max_prepared_transactions = 5        # can be 0 or more
# note: increasing max_prepared_transactions costs ~600 bytes of
shared memory
# per transaction slot, plus lock space (see
max_locks_per_transaction).
work_mem = 1024            # min 64, size in KB
maintenance_work_mem = 16384        # min 1024, size in KB
#max_stack_depth = 2048            # min 100, size in KB

# - Free Space Map -

#max_fsm_pages = 20000            # min max_fsm_relations*16, 6 bytes each
max_fsm_pages = 300000            # min max_fsm_relations*16, 6 bytes each
max_fsm_relations = 1000        # min 100, ~70 bytes each
#max_fsm_relations = 2000        # min 100, ~70 bytes each

# - Kernel Resource Usage -

#max_files_per_process = 1000        # min 25
#preload_libraries = ''

# - Cost-Based Vacuum Delay -

#vacuum_cost_delay = 0            # 0-1000 milliseconds
vacuum_cost_delay = 200            # 0-1000 milliseconds
#vacuum_cost_page_hit = 1        # 0-10000 credits
vacuum_cost_page_hit = 6        # 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_limit = 100        # 0-10000 credits

# - Background writer -

#bgwriter_delay = 200            # 10-10000 milliseconds 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 = 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        # in seconds, 0 is off

# - Archiving -

archive_command = ''            # command to use to archive a logfile
                    # segment
#Added, IChang, 11/28/2006 for restore
#archive_command = 'cp -f %p /home/csc/DB_HotBackup/archives/%f'


#---------------------------------------------------------------------------
# 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 = off
enable_sort = on
enable_tidscan = on

# - Planner Cost Constants -

#effective_cache_size = 1000        # typically 8KB each
effective_cache_size = 1300        # 2/3 of Ram
random_page_cost = 4            # units are one sequential page fetch
                    # cost
#cpu_tuple_cost = 0.01            # (same)
#cpu_index_tuple_cost = 0.001        # (same)
#cpu_operator_cost = 0.0025        # (same)

# - 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'        # 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
#redirect_stderr = off            # Enable capturing of stderr into log
                    # files

# These are only used if redirect_stderr is on:
log_directory = 'pg_log'        # Directory where log files are written
                    # Can be absolute or relative to PGDATA
#log_filename = 'postgresql-%Y-%m-%d_%H%M%S.log' # Log file name
pattern.
log_filename = 'postgresql-%a.log'    # Log file name pattern.
                    # Can include strftime() escapes
log_truncate_on_rotation = on           # 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 = 1440            # Automatic rotation of logfiles will
                    # happen after so many minutes.  0 to
                    # disable.
log_rotation_size = 0            # Automatic rotation of logfiles will
                    # happen after so many kilobytes of 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 = notice        # 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 = panic    # Values in order of increasing
severity:
                     #   debug5
                    #   debug4
                    #   debug3
                    #   debug2
                    #   debug1
                     #   info
                    #   notice
                    #   warning
                    #   error
                    #   panic(off)

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

#silent_mode = on            # DO NOT USE without syslog or
                    # redirect_stderr

# - What to Log -

#debug_print_parse = off
#debug_print_rewritten = off
#debug_print_plan = off
#debug_pretty_print = off
log_connections = off
#log_connections = on
log_disconnections = off
#log_disconnections = on
#log_duration = off
log_duration = on
#log_line_prefix = ''            # Special values:
#log_line_prefix = 'user=%u,db=%d'
log_line_prefix = '%t %p '        # 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, mod, ddl, all
#log_statement = 'all'            # none, mod, ddl, all
log_statement = 'mod'            # none, mod, ddl, all
#log_hostname = off


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

# - Statistics Monitoring -

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

# - Query/Index Statistics Collector -

stats_start_collector = on
#stats_command_string = off
#stats_block_level = off
#stats_row_level = off
stats_row_level = on
#stats_reset_on_server_start = off


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

#autovacuum = off            # enable autovacuum subprocess?
autovacuum = on                # enable autovacuum subprocess?
autovacuum_naptime = 20            # time between autovacuum runs, in secs
#autovacuum_vacuum_threshold = 1000    # min # of tuple updates before
autovacuum_vacuum_threshold = 1        # min # of tuple updates before
                    # vacuum
#autovacuum_analyze_threshold = 500    # min # of tuple updates before
autovacuum_analyze_threshold = 1    # min # of tuple updates before
                    # analyze
#autovacuum_vacuum_scale_factor = 0.4    # fraction of rel size before
autovacuum_vacuum_scale_factor = 0.1    # fraction of rel size before
                    # vacuum
autovacuum_analyze_scale_factor = 0.2    # fraction of rel size before
#autovacuum_analyze_scale_factor = 1    # fraction of rel size before
                    # analyze
#autovacuum_vacuum_cost_delay = -1    # default vacuum cost delay for
                    # autovac, -1 means use
                    # vacuum_cost_delay
#autovacuum_vacuum_cost_limit = -1    # default vacuum cost limit for
                    # autovac, -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, in milliseconds

# - Locale and Formatting -

#datestyle = 'iso, mdy'
#timezone = unknown            # actually, defaults to TZ
                    # environment setting
#australian_timezones = off
#extra_float_digits = 0            # min -15, max 2
#client_encoding = sql_ascii        # actually, defaults to database
client_encoding = BIG5            # actually, defaults to database
                    # encoding

# These settings are initialized by initdb -- they might be changed
#lc_messages = 'zh_TW.big5'            # locale for system error message
lc_messages = 'C'            # locale for system error message
                    # strings
#lc_monetary = 'zh_TW.big5'            # locale for monetary formatting
lc_monetary = 'C'            # locale for monetary formatting
#lc_numeric = 'zh_TW.big5'            # locale for number formatting
lc_numeric = 'C'            # locale for number formatting
#lc_time = 'zh_TW.big5'                # locale for time formatting
lc_time = 'C'                # locale for time formatting

# - Other Defaults -

#explain_pretty_print = on
#dynamic_library_path = '$libdir'


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

#deadlock_timeout = 1000        # in milliseconds
#max_locks_per_transaction = 64        # min 10
# note: each lock table slot uses ~220 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
#regex_flavor = advanced        # advanced, extended, or basic
#sql_inheritance = on
#default_with_oids = off
#escape_string_warning = off

# - Other Platforms & Clients -

#transform_null_equals = off


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

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