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help / color / mirror / Atom feedFrom: Charles Nadeau <[email protected]>
To: Scott Marlowe <[email protected]>
Cc: Mark Kirkwood <[email protected]>
Cc: pgsql-performa. <[email protected]>
Subject: Re: Very poor read performance, query independent
Date: Sun, 16 Jul 2017 11:22:00 +0200
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Scott,
The temp tablespace is on a disk of his own.
Thanks!
Charles
On Sat, Jul 15, 2017 at 7:58 PM, Scott Marlowe <[email protected]>
wrote:
> 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.
>
--
Charles Nadeau Ph.D.
http://charlesnadeau.blogspot.com/
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To: [email protected]
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Subject: Re: Very poor read performance, query independent
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