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Re: random_page_costs - are defaults of 4.0 realistic for SCSI RAID 1

From: Josh Berkus <josh(at)agliodbs(dot)com>
To: pgsql-performance(at)postgresql(dot)org
Cc: "Luke Lonergan" <llonergan(at)greenplum(dot)com>
Subject: Re: random_page_costs - are defaults of 4.0 realistic for SCSI RAID 1
Date: 2007-09-10 21:26:40
Message-ID: 200709101426.41424.josh@agliodbs.com (view raw or flat)
Thread:
Lists: pgsql-performance
Luke,

>  We (GP) have implemented
> something we call "Adaptive Nested Loop" to replace a nested loop +
> index scan with a hash join when the selectivity estimates are off in
> order to improve this behavior.  We also run with a
> "random_page_cost=100" because we generally run on machines with fast
> sequential I/O.

So, when is this getting contributed?  ;-)

-- 
--Josh

Josh Berkus
PostgreSQL @ Sun
San Francisco

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