Re: ToDo: log plans of cancelled queries

Pavel Stehule <pavel.stehule@gmail.com>

From: Pavel Stehule <pavel.stehule@gmail.com>
To: Stephen Frost <sfrost@snowman.net>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Simon Riggs <simon@2ndquadrant.com>, Alvaro Herrera <alvherre@2ndquadrant.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2013-01-11T16:31:59Z
Lists: pgsql-hackers
2013/1/11 Stephen Frost <sfrost@snowman.net>:
> * Tom Lane (tgl@sss.pgh.pa.us) wrote:
>> Simon Riggs <simon@2ndQuadrant.com> writes:
>> > An even better feature would be to be able to send a signal to a
>> > running query to log its currently executing plan. That way you can
>> > ask "Why so slow?" before deciding to kill it.
>>
>> That could conceivably work.  At least it wouldn't require running
>> EXPLAIN in a failed transaction.
>
> I like this idea, in general, also.  Taking that to the next level would
> be figuring out how you can do the same kind of thing through an
> interactive psql session where the user running the query doesn't need
> access to the database server or PG log files...
>

this is simple - it can be printed via elog(WARNING, ...) to original console

> We can send a 'cancel query', how about a 'report on query' which
> returns the plan and perhaps whatever other stats are easily available?

there is only one question - that POSIX signal we can use?

Pavel

>
>         Thanks,
>
>                 Stephen