Re: CPU and RAM - Mailing list pgsql-performance

From Qingqing Zhou
Subject Re: CPU and RAM
Date
Msg-id Pine.LNX.4.58.0512212258450.21276@eon.cs
Whole thread Raw
In response to CPU and RAM  (Harry Jackson <harryjackson@gmail.com>)
List pgsql-performance
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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