Re: What limits Postgres performance when the whole database lives in cache? - Mailing list pgsql-general

From Scott Marlowe
Subject Re: What limits Postgres performance when the whole database lives in cache?
Date
Msg-id CAOR=d=11Sy1iqHU3Lknc_dX2SB1CCqZJy3_UbLgZ5cpGOF7OEA@mail.gmail.com
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In response to What limits Postgres performance when the whole database lives in cache?  ("dandl" <david@andl.org>)
Responses Re: What limits Postgres performance when the whole database lives in cache?  (Andres Freund <andres@anarazel.de>)
Re: What limits Postgres performance when the whole database lives in cache?  ("dandl" <david@andl.org>)
List pgsql-general
On Fri, Sep 2, 2016 at 4:49 AM, dandl <david@andl.org> wrote:
> Re this talk given by Michael Stonebraker:
>
> http://slideshot.epfl.ch/play/suri_stonebraker
>
>
>
> He makes the claim that in a modern ‘big iron’ RDBMS such as Oracle, DB2, MS
> SQL Server, Postgres, given enough memory that the entire database lives in
> cache, the server will spend 96% of its memory cycles on unproductive
> overhead. This includes buffer management, locking, latching (thread/CPU
> conflicts) and recovery (including log file reads and writes).
>
>
>
> [Enough memory in this case assumes that for just about any business, 1TB is
> enough. The intent of his argument is that a server designed correctly for
> it would run 25x faster.]
>
>
>
> I wondered if there are any figures or measurements on Postgres performance
> in this ‘enough memory’ environment to support or contest this point of
> view?

What limits postgresql when everything fits in memory? The fact that
it's designed to survive a power outage and not lose all your data.

Stonebraker's new stuff is cool, but it is NOT designed to survive
total power failure.

Two totally different design concepts. It's apples and oranges to compare them.


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