Oracle FAQ Your Portal to the Oracle Knowledge Grid
HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US
 

Home -> Community -> Usenet -> c.d.o.server -> Re: CBO picks wrong plan after analyze. FIRST_ROWS hint is workaround. ALL_ROWS causes wrong plan

Re: CBO picks wrong plan after analyze. FIRST_ROWS hint is workaround. ALL_ROWS causes wrong plan

From: Sybrand Bakker <postbus_at_sybrandb.demon.nl>
Date: Thu, 21 Sep 2006 20:36:54 +0200
Message-ID: <6qm5h291afjmul7c1p8fdtdhhueo2rg9qv@4ax.com> 





On 21 Sep 2006 10:58:34 -0700, oracle10_at_gmail.com wrote:



>Are there cases when following Oracle Recommendation by frequent

>ANALYZE/stats gathering causes CBO to go astray?




Yes. That is one of the reasons why you should dbms_stats instead of
ANALYZE. Dbms_stats can save the old 'good' statistics to a stats
table, so you can easily restore them.


Also many people warn against frequent analysis.
IMO, I think frequent analysis, without saving the old statistics
(which seems to be the norm in my office) is just asking for trouble.


--
Sybrand Bakker, Senior Oracle DBA


Received on Thu Sep 21 2006 - 13:36:54 CDT












Original text of this message













  HOME |
  ASK QUESTION |
  ADD INFO |
  SEARCH |
  E-MAIL US