An ancient mystery

From: Dennis Williams <>
Date: Thu, 20 Nov 2008 21:05:16 -0600
Message-ID: <>


The situation:

Oracle database on Solaris 8 (soon to be upgraded to 10g) Rule-based Optimizer

A query which has run for years using an indexed access to a very large table (maybe 100 million rows)
suddenly decides to use a full-table scan, shutting down a critical business process.

Then after several hours, it switches back to using the index. All concerned claim that nothing changed before or after.

Needless to say the business users are nervous. They think maybe the database grew beyond some limit.

Can anyone think of an explanation?

Dennis Williams

Received on Thu Nov 20 2008 - 21:05:16 CST

Original text of this message