Re: Performance monitor - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Performance monitor
Date
Msg-id 14289.984004208@sss.pgh.pa.us
Whole thread Raw
In response to Re: Performance monitor  (Bruce Momjian <pgman@candle.pha.pa.us>)
Responses Re: Performance monitor  (Bruce Momjian <pgman@candle.pha.pa.us>)
List pgsql-hackers
Bruce Momjian <pgman@candle.pha.pa.us> writes:
> How do people feel about adding a single handler to 7.1?  Is it
> something I can slip into the current CVS, or will it have to exist as a
> patch to 7.1.  Seems it would be pretty isolated unless someone sends
> the signal, but it is clearly a feature addition.

> OK, I will distribute it as a patch.

Patch or otherwise, this approach seems totally unworkable.  A signal
handler cannot do I/O safely, it cannot look at shared memory safely,
it cannot even look at the backend's own internal state safely.  How's
it going to do any useful status reporting?

Firing up a separate backend process that looks at shared memory seems
like a more useful design in the long run.  That will mean exporting
more per-backend status into shared memory, however, and that means that
this is not a trivial change.
        regards, tom lane


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