Re: strange performance regression between 7.4 and 8.1 - Mailing list pgsql-performance

From Guido Neitzer
Subject Re: strange performance regression between 7.4 and 8.1
Date
Msg-id 2EB9B5FC-E7D5-46A7-8068-6C5D059E7781@event-s.net
Whole thread Raw
In response to Re: strange performance regression between 7.4 and 8.1  ("Alex Deucher" <alexdeucher@gmail.com>)
Responses Re: strange performance regression between 7.4 and 8.1  (Jeff Frost <jeff@frostconsultingllc.com>)
List pgsql-performance
On 02.03.2007, at 14:20, Alex Deucher wrote:

> Ah OK.  I see what you are saying;  thank you for clarifying.  Yes,
> the SAN is configured for maximum capacity; it has large RAID 5
> groups.  As I said earlier, we never intended to run a DB on the SAN,
> it just happened to come up, hence the configuration.

So why not dumping the stuff ones, importing into a PG configured to
use local discs (Or even ONE local disc, you might have the 16GB you
gave as a size for the db on the local machine, right?) and testing
whether the problem is with PG connecting to the SAN. So you have one
factor less to consider after all your changes.

Maybe it's just that something in the chain from PG to the actual HD
spindles kills your random access performance for getting the actual
rows.

cug

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