Re: Non-linear Performance - Mailing list pgsql-general

From Tom Lane
Subject Re: Non-linear Performance
Date
Msg-id 919.1022770699@sss.pgh.pa.us
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In response to Re: Non-linear Performance  ("Peter A. Daly" <petedaly@ix.netcom.com>)
Responses Re: Non-linear Performance
List pgsql-general
"Peter A. Daly" <petedaly@ix.netcom.com> writes:
> Tom Lane wrote:
>> Increasing SORT_MEM would help the constant factor, however...
>>
> What is the most amount of SORT_MEM it makes sense to allocate?

I've never experimented with it, but certainly the standard default
(512K = 0.5M) is pretty small for modern machines.  In a 2G machine
I might try settings around 100M-500M to see what works best.  (Note
this is just for a one-off btree creation --- for ordinary queries you
need to allow for multiple sorts going on in parallel, which is one
reason the default sort_mem is not very large.)

            regards, tom lane

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