Re: proposal 9.4. Explain on signal

On 16 May 2013 11:09, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> wrote:
> Hello
>
> I proposed a some months log plans of cancelled queries
> http://www.postgresql.org/message-id/CAFj8pRA-DuzkmDtu52CiUgb0P7TVri_B8LtjMJfWcnr1LPts6w@mail.gmail.com
> . After discussion the proposal was changed to get plan of any running
> query.
>
> I have a proof concept patch now and I am thinking so it can work well
>
> So I propose following concept:
>
> 1. function pg_explain_backend(PID int, loglevel int default 'log',
> explain_top_level boolean default true);
>
> Execution of this function ensure sending sigusr1 signal to PID process.
>
> 2. Sigusr1 handler will be enhanced for PROCSIG_EXPLAIN_MESSAGES
> message and it will write explain result to log.
>
>
> It share lot of code with auto_explain module. So I am thinking so we
> should move auto_explain functionality to core. Then EXPLAIN ON SIGNAL
> can be used for monitoring of query evaluating.

What a neat idea. So the original plan of EXPLAINing cancelled
queries... does this cater for that? Can cancelled queries
automatically invoke the EXPLAIN functionality as part of this
feature?

--
Thom