Re: [HACKERS] Changing the default configuration (was Re: - Mailing list pgsql-advocacy

From Tom Lane
Subject Re: [HACKERS] Changing the default configuration (was Re:
Date
Msg-id 932.1045027651@sss.pgh.pa.us
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In response to Re: Changing the default configuration (was Re:  (Peter Eisentraut <peter_e@gmx.net>)
Responses Re: [HACKERS] Changing the default configuration (was Re:
Re: [HACKERS] Changing the default configuration (was Re:
Re: [HACKERS] Changing the default configuration (was Re:
List pgsql-advocacy
Peter Eisentraut <peter_e@gmx.net> writes:
> Tom Lane writes:
>> We could retarget to try to stay under SHMMAX=4M, which I think is
>> the next boundary that's significant in terms of real-world platforms
>> (isn't that the default SHMMAX on some BSDen?).  That would allow us
>> 350 or so shared_buffers, which is better, but still not really a
>> serious choice for production work.

> What is a serious choice for production work?

Well, as I commented later in that mail, I feel that 1000 buffers is
a reasonable choice --- but I have to admit that I have no hard data
to back up that feeling.  Perhaps we should take this to the
pgsql-perform list and argue about reasonable choices.

A separate line of investigation is "what is the lowest common
denominator nowadays?"  I think we've established that SHMMAX=1M
is obsolete, but what replaces it as the next LCD?  4M seems to be
correct for some BSD flavors, and I can confirm that that's the
current default for Mac OS X --- any other comments?

            regards, tom lane

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