These parameters control server-wide statistics collection
features. When statistics collection is enabled, the data that
is produced can be accessed via the
pg_statio family of system views. Refer to
for more information.
Enables the collection of information on the currently executing command of each session, along with the time when 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.
Specifies the number of bytes reserved to track the
currently executing command for each active session, for
query field. The default value is
1024. This parameter can only be set at server start.
Enables collection of statistics on database activity. This parameter is on by default, because the autovacuum daemon needs the collected information. Only superusers can change this setting.
Enables timing of database I/O calls. This parameter
is off by default, because it will repeatedly query the
operating system for the current time, which may cause
significant overhead on some platforms. You can use the
pg_test_timing tool to
measure the overhead of timing on your system. I/O timing
information is displayed in pg_stat_database,
in the output of EXPLAIN when the
BUFFERS option is used, and by pg_stat_statements.
Only superusers can change this setting.
Enables tracking of function call counts and time
pl to track
only procedural-language functions,
all to also track SQL and C language
functions. The default is
none, which disables function statistics
tracking. Only superusers can change this setting.
SQL-language functions that are simple enough to be “inlined” into the calling query will not be tracked, regardless of this setting.
Sets the directory to store temporary statistics data
in. This can be a path relative to the data directory or
an absolute path. The default is
pg_stat_tmp. Pointing this at a
RAM-based file system will decrease physical I/O
requirements and can lead to improved performance. This
parameter can only be set in the
postgresql.conf file or on the server
For each query, output performance statistics of the
respective module to the server log. This is a crude
profiling instrument, similar to the Unix
getrusage() operating system facility.
total statement statistics, while the others report
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.
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