Cost-Based Optimizer and AIX Virtual Processors

From: David Barbour <>
Date: Wed, 29 Apr 2009 16:12:19 -0400
Message-ID: <>

Has anyone seen execution plans change using virtual processors on AIX? How about VM/Linux or VM/Windows? For the purposes of the optimizer, I'd think they'd all react in a similar manner.

We've got several partitions on an AIX system. If a specific instance has a certain allotment of processors (generally >=2) when a query kicks off, it runs differently than when the instance is basically idle (<= 1 processor allocated) and the query starts.

Received on Wed Apr 29 2009 - 15:12:19 CDT

Original text of this message