Richard Huxton wrote:
Dave Cramer wrote:

On 18-Nov-05, at 1:07 AM, Luke Lonergan wrote:

Postgres + Any x86 CPU from 2.4GHz up to Opteron 280 is CPU bound after
110MB/s of I/O.  This is true of Postgres 7.4, 8.0 and 8.1.

A $1,000 system with one CPU and two SATA disks in a software RAID0 will perform exactly the same as a $80,000 system with 8 dual core CPUs and the world's best SCSI RAID hardware on a large database for decision support
(what the poster asked about).

Now there's an interesting line drawn in the sand. I presume you have numbers to back this up ?

This should draw some interesting posts.

That's interesting, as I occasionally see more than 110MB/s of postgresql IO on our system. I'm using a 32KB block size, which has been a huge win in performance for our usage patterns. 300GB database with a lot of turnover. A vacuum analyze now takes about 3 hours, which is much shorter than before. Postgresql 8.1, dual opteron, 8GB memory, Linux 2.6.11, FC drives.

-- Alan

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