Re: Why CBO doesn't choose the low cost plan
- From: "eagle fan" <eagle.f@xxxxxxxxx>
- To: "Jared Still" <jkstill@xxxxxxxxx>, oracle-l@xxxxxxxxxxxxx
- Date: Thu, 20 Jul 2006 13:20:25 +0800
I create a empty table with the same table/index structure in 18.104.22.168 & 22.214.171.124 test environments and exp/imp the table/index statistics into test environments.
The 9i test database still chose the bad index, but *8i test database chose the right plan.*
Even when I set the *ANONYMOUS_CE_IDX index's *statistics to very big value, it still chose the bad one.
I agree that this maybe a 126.96.36.199 bug.
On 7/19/06, Jared Still <jkstill@xxxxxxxxx> wrote:
On 7/19/06, eagle fan <eagle.f@xxxxxxxxx> wrote:
> hi: > > My oracle version is 9205 and optimizer_features_enable is set to 9.2.0. > > We have a query choose a bad plan. > > ... > What do you think? >
I think it's a bug.
A possible candidate is *Bug 4112254 - CBO may not choose best index for single table access with unpeeked bind/function*
I just searched MetaLink on CBO Bug 188.8.131.52
You should probably check there.
-- Jared Still Certifiable Oracle DBA and Part Time Perl Evangelist
-- Eagle Fan