Horton

Re: [Testperf-general] Re: First set of OSDL Shared Memscalability results, some wierdness ...

Josh Berkus <josh@agliodbs.com>

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From: Josh Berkus <josh@agliodbs.com>
To: pgsql-performance@postgresql.org
Cc: Tom Lane <tgl@sss.pgh.pa.us>, "Simon Riggs" <simon@2ndquadrant.com>, "Timothy D. Witham" <wookie@osdl.org>, testperf-general@pgfoundry.org
Date: 2004-10-15T20:13:13Z
Lists: pgsql-hackers, pgsql-performance 
Tom, Simon:

First off, two test runs with OProfile are available at:
http://khack.osdl.org/stp/298124/
http://khack.osdl.org/stp/298121/

> AtEOXact_Buffers
>         transaction commit or abort
> UnlockBuffers
>         transaction abort, backend exit

Actually, this might explain the "hump" shape of the curve for this test.  
DBT2 is an OLTP test, which means that (at this scale level) it's attempting 
to do approximately 30 COMMITs per second as well as one ROLLBACK every 3 
seconds.    When I get the tests on DBT3 running, if we see a more gentle 
dropoff on overallocated memory, it would indicate that the above may be a 
factor.

-- 
--Josh

Josh Berkus
Aglio Database Solutions
San Francisco