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From: Jeff Janes <[email protected]>
To: Charles Nadeau <[email protected]>
Cc: [email protected] <[email protected]>
Subject: Re: Very poor read performance, query independent
Date: Mon, 10 Jul 2017 12:24:04 -0700
Message-ID: <CAMkU=1z92pimpoDV1oTpd4AvSHS0CrLzQDFSxw1Z5cpmmjEOkw@mail.gmail.com> (raw)
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On Mon, Jul 10, 2017 at 7:03 AM, Charles Nadeau <[email protected]>
wrote:

>
> The problem I have is very poor read. When I benchmark my array with fio I
> get random reads of about 200MB/s and 1100IOPS and sequential reads of
> about 286MB/s and 21000IPS.
>


That doesn't seem right.  Sequential is only 43% faster?  What job file are
giving to fio?

What do you get if you do something simpler, like:

time cat ~/$PGDATA/base/16402/*|wc -c

replacing 16402 with whatever your biggest database is.

Cheers,

Jeff


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