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Re: Scary 10gR2 query problem

From: fairlie rego <fairlie_r_at_yahoo.com>
Date: Wed, 24 May 2006 06:28:34 -0700 (PDT)
Message-ID: <20060524132834.90302.qmail@web31913.mail.mud.yahoo.com>


Hi Ian,    

  Assuming the problem is with the optimizer do you get correct results if you   set optimizer_features_enable to 10.1.0 at the session level?   

Regards,
  Fairlie
"Ian Cary (C)" <Ian.Cary_at_ordnancesurvey.co.uk> wrote:   

As there seem to a few people using 10.2 (10.2.0.2 on Solaris 9 in my case) I thought I'd share a scary issue with you all.

Odd in the example below is a reasonably complex view that has been working fine in 10.1 for quite a while.

MP409SH2> select count(*) from odd;

COUNT(*)



67311

Elapsed: 00:01:15.56
MP409SH2> create table very_odd as select * from odd;

Table created.

Elapsed: 00:07:34.00
MP409SH2> select count(*) from very_odd;

COUNT(*)



1371016

Elapsed: 00:00:01.84

This is a 100% genuine case where the select statement returns the wrong (substantially) number of rows. In 10.1 the view returns the correct 67311 rows.
There doesn't seem to be any pattern or reason for the error and I only noticed it because I had the 10.1 results to hand. I'll be raising a tar as soon as Metalink sorts itself out but I thought I'd share this as I'm not sure I can 100% trust the results of any select statement on 10.2

Cheers,

Ian
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          Fairlie Rego
Senior Oracle Consultant
  Optus Telecommunications
  www.optus.com.au                     



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http://www.freelists.org/webpage/oracle-l Received on Wed May 24 2006 - 08:28:34 CDT

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