Here's a cleaned-up copy of the doc text. Send a request to the backend with the specified process ID to log its backtrace. The backtrace will be logged at message level <literal>LOG</literal>. It will appear in the server log based on the log configuration set (See <xref linkend="runtime-config-logging"/> for more information), but will not be sent to the client regardless of <xref linkend="guc-client-min-messages"/>. A backtrace will identify where exactly the backend process is currently executing. This may be useful to developers to diagnose stuck processes and other problems. This feature is not supported for the postmaster, logger, or statistics collector process. This feature will be available if PostgreSQL was built with the ability to capture backtracee. If not available, the function will return false and show a WARNING. Only superusers can request backends to log their backtrace.
> - * this and related functions are not inlined. > + * this and related functions are not inlined. If edata pointer is valid > + * backtrace information will set in edata. will *be* set -- Justin