Re: AIX slow buffer reads - Mailing list pgsql-performance

From Tom Lane
Subject Re: AIX slow buffer reads
Date
Msg-id 29868.1288219499@sss.pgh.pa.us
Whole thread Raw
In response to Re: AIX slow buffer reads  (Brad Nicholson <bnichols@ca.afilias.info>)
List pgsql-performance
Brad Nicholson <bnichols@ca.afilias.info> writes:
> On 10/27/2010 4:10 PM, Tom Lane wrote:
>> AFAICT from googling, AIX does have posix_fadvise, though maybe it
>> doesn't do anything useful ...

> If there is an easy way to check if it does do anything useful?  If so,
> I can check it out.

If you don't see any performance change in bitmap scans between
effective_io_concurrency = 0 and effective_io_concurrency = maybe 4 or
so, then you could probably conclude it's a no-op.

            regards, tom lane

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