RE: index hint returns wrong results

I wouldn't trust the execution plan 100%.
Since it's a global index that meets one of the requirements - so what are the two rowids ?
The starting bytes give the data_object_id - are they the same for the two rows; alternatively what does a call to dbms_mview.pmarker(rowid) give for the two rows.


Regards
Jonathan Lewis
http://jonathanlewis.wordpress.com
_at_jloracle

________________________________________
From: Terrian, Thomas J CTR (US) [Tom.Terrian.ctr_at_dla.mil]
Sent: 08 March 2016 13:50
To: Jonathan Lewis; oracle-l_at_freelists.org
Subject: RE: index hint returns wrong results

That is interesting.

Even when I use the partition name, I still get bad results:

select /*+ index(t1 ind1) */ count(*)
from scott.t1 partition (sys_p14)
where f1 = 'one' and f2 = ' ';

  COUNT(*)
----------
         2

There is only 1 row in that table where f1 = 'one' and f2 = ' '.

And I see partition pruning in the explain plan when it tries to access the table (not for the global index of course).


-----Original Message-----
From: Jonathan Lewis [mailto:jonathan_at_jlcomp.demon.co.uk]
Sent: Tuesday, March 08, 2016 8:05 AM
To: Terrian, Thomas J CTR (US); oracle-l_at_freelists.org
Subject: [Non-DoD Source] RE: index hint returns wrong results


If the table is partitioned then I think it's possible for the error to appear as a result of procedural error on the part of the application.

I'd have to check but I think you might be able to do an exchange partition including indexes without validation that got data into the wrong partition which wouldn't be seen by a (partition eliminating) tablescan but was seen by a range scan of a global index.

This may be version dependent, of course thanks to enhancements in global index usage.



Regards
Jonathan Lewis
http://jonathanlewis.wordpress.com
_at_jloracle

________________________________________
From: oracle-l-bounce_at_freelists.org [oracle-l-bounce_at_freelists.org] on behalf of Terrian, Thomas J CTR (US) [Tom.Terrian.ctr@dla.mil]
Sent: 08 March 2016 12:32
To: oracle-l_at_freelists.org
Subject: index hint returns wrong results

Oracle 12c.

Am I missing something or is this a bug?  Using an index hint returns the wrong results.  Does it matter if the table is partitioned and the index is global or even what fields are in the index?  I can't see how any of that should matter.  The results should be the same:


select /*+ index(t1 ind1) */ count(*)
from scott.t1
where f1 = 'one' and f2 = ' ';

  COUNT(*)
----------
         2

select count(*)
from scott.t1
where f1 = 'one' and f2 = ' ';

  COUNT(*)
----------
         1


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