Re: explain plan and the real execution plan
From: Yong Huang <yong321_at_yahoo.com>
Date: Fri, 20 Nov 2009 08:13:59 -0800 (PST)
Message-ID: <101322.54130.qm_at_web80602.mail.mud.yahoo.com>
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.
Date: Fri, 20 Nov 2009 08:13:59 -0800 (PST)
Message-ID: <101322.54130.qm_at_web80602.mail.mud.yahoo.com>
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
-- http://www.freelists.org/webpage/oracle-lReceived on Fri Nov 20 2009 - 10:13:59 CST