Re: Postgres not using array - Mailing list pgsql-performance

From Mark Mielke
Subject Re: Postgres not using array
Date
Msg-id 48AD78C8.80500@mark.mielke.cc
Whole thread Raw
In response to Re: Postgres not using array  (André Volpato<andre.volpato@ecomtecnologia.com.br>)
List pgsql-performance
André Volpato wrote:
> In practice, I have noticed that dual 1.8 is worse than single 3.0. We
> have another server wich
> is a Pentium D 3.0 GHz, that runs faster.
> ...
> Postgres read the array in less than 1 sec, and the other 10s he takes
> 100% of CPU usage,
> wich is, in this case, one of the two cores at 1.8GHz.
>
> I am a bit confused about what CPU is best for Postgres. Our apps is
> mostly read, with
> a few connections and heavy queryes.
> Does it worth a multi-core ?

How are you doing your benchmarking? If you have two or more queries
running at the same time, I would expect the 1.8 Ghz x 2 to be
significant and possibly out-perform the 3.0 Ghz x 1. If you usually
only have one query running at the same time, I expect the 3.0 Ghz x 1
to always win. PostgreSQL isn't good at splitting the load from a single
client across multiple CPU cores.

Cheers,
mark

--
Mark Mielke <mark@mielke.cc>


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