Re: Scary 10gR2 query problem

Does your reasonably complex view happen to make use of "connect by" and the analytic function "first_value()" ? We had a very similar problem, in that a query written (improperly) in 9.2.0.4 would return a given number of rows, using a connect-by query where part of the join criteria made use of "first_value( col ) over ()". We did not have an explicit "order by" on the partition clause of the analytic function, and proper results were (thankfully) returned in 9.2.0.4.

Results were quite different in 10.2.0.2, since the ordering of the partition changed (similar to the ordering being shifted in a "group by" query). We do understand the reason behind all of this, but it was quite disconcerting.

HTH Glenn

On 5/24/06, 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
> .
>
>
> This email is only intended for the person to whom it is addressed and may contain confidential information. If you have received this email in error, please notify the sender and delete this email which must not be copied, distributed or disclosed to any other person.
>
> Unless stated otherwise, the contents of this email are personal to the writer and do not represent the official view of Ordnance Survey. Nor can any contract be formed on Ordnance Survey's behalf via email. We reserve the right to monitor emails and attachments without prior notice.
>
> Thank you for your cooperation.
>
> Ordnance Survey
> Romsey Road
> Southampton SO16 4GU
> Tel: 023 8079 2000
> http://www.ordnancesurvey.co.uk
>
> --
> http://www.freelists.org/webpage/oracle-l
>
>
>

--
http://www.freelists.org/webpage/oracle-l