<varname>pg_stat_statements.track_planning</varname> controls whether

planning operations and duration are tracked by the module.

Enabling this parameter may incur a noticeable performance penalty,

especially when a fewer kinds of queries are executed on many

concurrent connections.

especially when statements with identical query structure are executed

by many concurrent connections which compete to update a small number of

<structname>pg_stat_statements</structname> entries.

The default value is <literal>off</literal>.

Only superusers can change this setting.

</para>