From: Qingqing Zhou <zhouqq@cs.toronto.edu>
To: Harry Jackson <harryjackson@gmail.com>
Subject: Re: CPU and RAM
Date: Wed, 21 Dec 2005 23:01:12 -0500
Message-ID: <Pine.LNX.4.58.0512212258450.21276@eon.cs> (raw)
In-Reply-To: <45b42ce40512211720t164ea389wa5bfd0cbae6c80e2@mail.gmail.com>
References: <45b42ce40512211720t164ea389wa5bfd0cbae6c80e2@mail.gmail.com>
On Thu, 22 Dec 2005, Harry Jackson wrote:
> I am currently using a dual Opteron (248) single core system (RAM
> PC3200) and for a change I am finding that the bottleneck is not disk
> I/O but CPU/RAM (not sure which). The reason for this is that the most
> frequently accessed tables/indexes are all held in RAM and when
> querying the database there is almost no disk activity which is great,
> most of the time.
>
> At the moment everything is working OK but I am noticing an almost
> linear increase in time to retrieve data from the database as the data
> set increases in size. Clustering knocks the access times down by 25%
Let's find out what's going on first. Can you find out the most expensive
query. Also, according to you what you said: (1) execution time is linear
to data set size (2) no disk IO - so why cluster will improve 25%?
Regards,
Qingqing
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To: pgsql-performance@postgresql.org
Cc: zhouqq@cs.toronto.edu, harryjackson@gmail.com
Subject: Re: CPU and RAM
In-Reply-To: <Pine.LNX.4.58.0512212258450.21276@eon.cs>
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