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.

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 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 by using the Process Explorer. Only superusers can change this setting.

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.