Re: RAM-only temporary tables - Mailing list pgsql-hackers

From Alvaro Herrera
Subject Re: RAM-only temporary tables
Date
Msg-id 20081106162208.GH5520@alvh.no-ip.org
Whole thread Raw
In response to Re: RAM-only temporary tables  ("Kevin Grittner" <Kevin.Grittner@wicourts.gov>)
List pgsql-hackers
Kevin Grittner wrote:

> It sounds like you were counting the 8kB pages pushed from the
> PostgreSQL cache to the OS cache, and I was counting the 1kB blocks
> pushed from the OS cache to the RAID controller cache.  By watching
> vmstat results after pushing this to a more-or-less steady state, I
> was probably picking up the results of autovacuum runs, but multiple
> writes to a single page were often combined by the OS.  If we match,
> it's really just a coincidence.

I was counting WAL inserts actually, so "logical database operations".
I left out "storage" items (filesystem actions), so it was mainly just
catalog changes.

-- 
Alvaro Herrera                                http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support


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