These parameters control a server-wide statistics collection feature.
When statistics collection is enabled, the data that is produced can be
accessed via the pg_stat
and
pg_statio
family of system views.
Refer to Chapter 25, Monitoring Database Activity for more information.
As of PostgreSQL 8.2,
stats_command_string
controls a separate data
collection mechanism that can be turned on or off independently
of whether the statistics-collection subprocess is running.
The subprocess is only needed to support collection of
block-level or row-level statistics.
stats_command_string
(boolean
)
Enables the collection of information on the currently executing command of each session, along with the time at which that command began execution. This parameter is on by default. Note that even when enabled, this information is not visible to all users, only to superusers and the user owning the session being reported on; so it should not represent a security risk. Only superusers can change this setting.
update_process_title
(boolean
)
Enables updating of the process title every time a new SQL command
is received by the server. The process title is typically viewed
by the ps
command or in Windows using the Process
Explorer. Only superusers can change this setting.
stats_start_collector
(boolean
)
Controls whether the server should start the statistics-collection subprocess. This is on by default, but may be turned off if you know you have no interest in collecting statistics or running autovacuum. This parameter can only be set at server start, because the collection subprocess cannot be started or stopped on-the-fly. (However, the extent to which statistics are actually gathered can be changed while the server is running, so long as the subprocess exists.)
stats_block_level
(boolean
)
Enables the collection of block-level statistics on database activity. This parameter is off by default. Only superusers can change this setting.
stats_row_level
(boolean
)
Enables the collection of row-level statistics on database activity. This parameter is off by default. Only superusers can change this setting.
stats_reset_on_server_start
(boolean
)
If on, collected block-level and row-level statistics are zeroed out whenever the server is restarted. If off, statistics are accumulated across server restarts. This parameter is off by default. This parameter can only be set at server start.
log_statement_stats
(boolean
)log_parser_stats
(boolean
)log_planner_stats
(boolean
)log_executor_stats
(boolean
)
For each query, write performance statistics of the respective
module to the server log. This is a crude profiling
instrument. log_statement_stats
reports total
statement statistics, while the others report per-module statistics.
log_statement_stats
cannot be enabled together with
any of the per-module options. All of these options are disabled by
default. Only superusers can change these settings.