V6.0.33 bug on indexed retrievals??

Has anyone out there come across this "feature" under ORACLE V6.0.33 ??

   Symptom:        Indexed queries of a large table suddenly take 10 times as 
                   long as usual.
   
   Investigations: VALIDATE INDEX performed - Index validated, no performance
                   improvement.

                   Index dropped/recreated - no performance improvement.

                   Index dropped, data exported, table dropped/recreated, data
                   imported, index recreated - Performance returns to expected
                   speed

                   Each retrieval attempt was performed twice, once with the 
                   TRACE option switched on. In all cases the EXPLAIN PLAN 
                   indicated that it was an indexed retrieval.
   
   Conclusion:     The index appears to become unusable, but the Dictionary 
                   and the VALIDATE INDEX options are unable to recognise 
                   this. The fact that dropping/recreating the index does not
                   clear the problem is confusing.

 This is not a common problem, (it has ocurred twice in 18 months), but the ORACLE Help desk assures me they have not had any other occurrences reported to them before (or since?)

• Has anyone got any ideas????

Cheers,
Martin. Received on Thu Apr 07 1994 - 17:57:29 CEST