Re: explain plan and the real execution plan

From: Yong Huang <>
Date: Fri, 20 Nov 2009 08:13:59 -0800 (PST)
Message-ID: <>

In addition, if the queries against this table recently started to use columns not used before, the content of col_usage$ will change thus affecting the stats related to auto generated historgram.

Yong Huang

Tanel Poder wrote:

> 1) The optimizer statistics
> I assume this database has no change – no ddl and dml. Under this
> situation, I would say the optimizer statistics would remain the same,
> correct?

Even if you have no DDL and no DML happening, someone may still have gathered optimizer statistics on the tables and changed them. Maybe the last       

Received on Fri Nov 20 2009 - 10:13:59 CST

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