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help / color / mirror / Atom feedFrom: Scott Marlowe <[email protected]>
To: Charles Nadeau <[email protected]>
Cc: Mark Kirkwood <[email protected]>
Cc: pgsql-performa. <[email protected]>
Subject: Re: Very poor read performance, query independent
Date: Sat, 15 Jul 2017 11:58:32 -0600
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On Sat, Jul 15, 2017 at 11:53 AM, Charles Nadeau
<[email protected]> wrote:
> Mark,
>
> I increased the read ahead to 16384 and it doesn't improve performance. My
> RAID 0 use a stripe size of 256k, the maximum size supported by the
> controller.
Are your queries still spilling to disk for sorts? If this is the
case, and they're just too big to fit in memory, then you need to move
your temp space, where sorts happen, onto another disk array that
isn't your poor overworked raid-10 array. Contention between sorts and
reads can kill performance quick, esp on spinning rust.
--
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To: [email protected]
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Subject: Re: Very poor read performance, query independent
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