RE: index hint returns wrong results

I'm not sure that I can agree with you, Mark.

What if you get "wrong results" because you set the query_rewrite_integrity ?
It's not quite the same, but you've said to Oracle that you will be responsible for wrong results.

Similarly what if you set a constraint to RELY disable novalidate and then break it. You volunteered to get wrong results.

If you tell Oracle that you don't want it to validate the data that you've put into the wrong partition why should Oracle be at fault when you get the wrong results ?

(That's assuming my suggested scenario is correct, of course - I'll try to build a model this evening).

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

________________________________________
From: Mark W. Farnham [mwf_at_rsiz.com]
Sent: 08 March 2016 16:23
To: Tom.Terrian.ctr_at_dla.mil; Jonathan Lewis; oracle-l_at_freelists.org
Subject: RE: index hint returns wrong results

First, let's be clear: If Oracle returns incorrect results, then there most
definitely is a bug in the stack somewhere. Even if the data has been
FUBAR'd due to PEBKAC, it is incumbent on the RDBMS to prevent delivery of a
response without tossing an error.

Second, mmm, it seems to me it would be very useful to try to develop a
degenerate (meaning no more complicated than required) case from creation
and population scripts to wrong results so others can help isolate which
versions may be affected and any required "avoid doing this" work-around
advice to the community until the bug is fixed.

mwf

-----Original Message-----
From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org]
On Behalf Of Terrian, Thomas J CTR (US)
Sent: Tuesday, March 08, 2016 8:51 AM
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_at_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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