Re: Performance monitor signal handler - Mailing list pgsql-hackers

From Philip Warner
Subject Re: Performance monitor signal handler
Date
Msg-id 3.0.5.32.20010313132237.032525c0@mail.rhyme.com.au
Whole thread Raw
In response to Re: Performance monitor signal handler  (Alfred Perlstein <bright@wintelcom.net>)
Responses Re: Performance monitor signal handler  (Alfred Perlstein <bright@wintelcom.net>)
Re: Performance monitor signal handler  (Bruce Momjian <pgman@candle.pha.pa.us>)
List pgsql-hackers
At 13:34 12/03/01 -0800, Alfred Perlstein wrote:
>Is it possible
>to have a spinlock over it so that an external utility can take a snapshot
>of it with the spinlock held?

I'd suggest that locking the stats area might be a bad idea; there is only
one writer for each backend-specific chunk, and it won't matter a hell of a
lot if a reader gets inconsistent views (since I assume they will be
re-reading every second or so). All the stats area should contain would be
a bunch of counters with timestamps, I think, and the cost up writing to it
should be kept to an absolute minimum.


>
>just some ideas..
>

Unfortunatley, based on prior discussions, Bruce seems quite opposed to a
shared memory solution.


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