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MA46186 - OSP-PERFM INDEX NOT USED DUE TO INCORRECT 'IS NOT NULL' EKR
ESTIMATE

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 APAR (Authorized Program Analysis Report)

Abstract

OSP-PERFM INDEX NOT USED DUE TO INCORRECT 'IS NOT NULL' EKR
ESTIMATE

Error Description

EKR was giving an estimate of 100% for the IsNotNull when      
actually all rows are Null for a particular column. This        
invalid estimate caused the desirable index to not be used.    

Problem Summary

EKR was giving an estimate of 100% for the IsNotNull when      
actually all rows are Null for a particular column. This invalid
estimate caused the desirable index to not be used.            

Problem Conclusion

The algorithm for calculating the number of non-NULL values for
a given key was found to have a bug that resulted in an estimate
of 100% when it should have been 0%.  The estimate problem is  
specific to EKRs that are trying to determine the non-NULL      
count.                                                          

Temporary Fix

Comments

Circumvention


PTFs Available

R710 MF63321 PTF Cover Letter   1000
R720 MF63213 PTF Cover Letter   7290
R730 MF63539 PTF Cover Letter   7283

Affected Modules

         
         

Affected Publications

Summary Information

Status............................................ CLOSED PER
HIPER........................................... No
Component.................................. 9400DG3DB
Failing Module.......................... RCHMGR
Reported Release................... R720
Duplicate Of..............................




System i Support

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Document Information

Modified date:
28 October 2017