Re: Replication Syatem - Mailing list pgsql-performance

From Tom Lane
Subject Re: Replication Syatem
Date
Msg-id 18879.1209567759@sss.pgh.pa.us
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In response to Replication Syatem  ("Gauri Kanekar" <meetgaurikanekar@gmail.com>)
List pgsql-performance
fche@redhat.com (Frank Ch. Eigler) writes:
> Tom Lane <tgl@sss.pgh.pa.us> writes:
>> Also, you need to make sure you have the FSM parameters set high enough
>> so that all the free space found by a VACUUM run can be remembered.

> Would it be difficult to arrange FSM parameters to be automatically
> set from the VACUUM reclaim results?

Yeah, because the problem is that FSM is kept in shared memory which
cannot be resized on-the-fly.

In retrospect, trying to keep FSM in shared memory was a spectacularly
bad idea (one for which I take full blame).  There is work afoot to
push it out to disk so that the whole problem goes away; so I don't see
much point in worrying about band-aid solutions.

            regards, tom lane

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