Re: PG as in-memory db? How to warm up and re-populate buffers? How to read in all tuples into memory?

From: Stefan Keller <sfkeller(at)gmail(dot)com>
To: Andy Colson <andy(at)squeakycode(dot)net>
Cc: pgsql-performance(at)postgresql(dot)org, Stephen Frost <sfrost(at)snowman(dot)net>
Subject: Re: PG as in-memory db? How to warm up and re-populate buffers? How to read in all tuples into memory?
Date: 2012-02-26 19:11:24
Message-ID: CAFcOn2-n=fCmJEwB81V-SDo00RzTPrQbrh=GAgxoE1DWLqhtDw@mail.gmail.com
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2012/2/26 Andy Colson <andy(at)squeakycode(dot)net> wrote:
> On 02/25/2012 06:16 PM, Stefan Keller wrote:
>> 1. How can I warm up or re-populate shared buffers of Postgres?
>> 2. Are there any hints on how to tell Postgres to read in all table
>> contents into memory?
>>
>> Yours, Stefan
>
> How about after you load the data, vacuum freeze it, then do something like:
>
> SELECT count(*) FROM osm_point WHERE tags @> 'tourism=>junk'
>
> -Andy

That good idea is what I proposed elsewhere on one of the PG lists and
got told that this does'nt help.

I can accept this approach that users should'nt directly interfere
with the optimizer. But I think it's still worth to discuss a
configuration option (per table) or so which tells PG that this table
contents should fit into memory so that it tries to load a table into
memory and keeps it there. This option probably only makes sense in
combination with unlogged tables.

Yours, Stefan

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