proposal 9.4. Explain on signal - Mailing list pgsql-hackers

From Pavel Stehule
Subject proposal 9.4. Explain on signal
Date
Msg-id CAFj8pRDEo24joEg4UFRDYeFADFTw-jw_=t=kPwOyDW=v=g1Fhg@mail.gmail.com
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Responses Re: proposal 9.4. Explain on signal  (Thom Brown <thom@linux.com>)
List pgsql-hackers
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.

Regards

Pavel

comments?



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