Causes the duration of every completed statement to be logged. The default is
off. Only superusers can change this setting.
For clients using extended query protocol, durations of the Parse, Bind, and Execute steps are logged independently.
The difference between setting this option and setting log_min_duration_statement to zero is that exceeding log_min_duration_statement forces the text of the query to be logged, but this option doesn't. Thus, if
on and log_min_duration_statement has a positive value, all durations are logged but the query text is included only for statements exceeding the threshold. This behavior can be useful for gathering statistics in high-load installations.