Re: [ADMIN] Help bad results with pgbench - Mailing list pgsql-admin

From Scott Marlowe
Subject Re: [ADMIN] Help bad results with pgbench
Date
Msg-id CAOR=d=0R1GOBWQ8PEJf7EAc3wgTUX2MxggkJTLp3GgnGJyp3yQ@mail.gmail.com
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In response to Re: [ADMIN] Help bad results with pgbench  (Scott Marlowe <scott.marlowe@gmail.com>)
Responses Re: [ADMIN] Help bad results with pgbench  ("Lazaro Garcia" <lazaro3487@gmail.com>)
List pgsql-admin
On Mon, Apr 10, 2017 at 9:48 AM, Scott Marlowe <scott.marlowe@gmail.com> wrote:
> On Mon, Apr 10, 2017 at 9:09 AM, Lazaro Garcia <lazaro3487@gmail.com> wrote:
>> Good morning everyone.
>>
>> I'm having the following problem with pgbench and test again:
>
> Yeah this is the file system cache warm vs cold. In the first instance
> everything fits in RAM (or most of it) and is there because it's been
> accessed. When you reboot the machine is "warming up" so to speak the
> file system cache. Often just running select * from table is all you
> need to warm them up yourself.

So -i 200 is only a couple of gigs. You should fill up the file system
cache pretty fast.

Just keep running pgbench and the numbers should climb over time.

Or you can look into the pg_prewarm module.

https://www.postgresql.org/docs/9.4/static/pgprewarm.html

--
To understand recursion, one must first understand recursion.


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