IBM Support

MA44668 - OSP-OTHER-PERFM SUBOPTIMAL INDEXES BEING CHOSEN CAUSING POOR
PERFORMING ACCESS PLAN TO BE CHOSEN 15/06/11 PTF PECHANGE

Subscribe to this APAR

By subscribing, you receive periodic emails alerting you to the status of the APAR, along with a link to the fix after it becomes available. You can track this item individually or track all items by product.

Notify me when this APAR changes.

Notify me when an APAR for this component changes.

 APAR (Authorized Program Analysis Report)

Abstract

OSP-OTHER-PERFM SUBOPTIMAL INDEXES BEING CHOSEN CAUSING POOR
PERFORMING ACCESS PLAN TO BE CHOSEN 15/06/11 PTF PECHANGE

Error Description

After PTFs applied, some queries                                
started using a less then optimal index even though better      
indexes exists. This resulted in poor performing access plans  
been chosen.                                                    

Problem Summary

****************************************************************
* PROBLEM: (MA44668) Licensed Program = 5770999 for i 7.1 and  *
*                                       i 7.2                  *
*           Usability of a Product's MAJOR Function            *
*            Query Optimization performance degradation        *
****************************************************************
* USERS AFFECTED: All IBM i operating system users.            *
****************************************************************
* RECOMMENDATION: Apply LIC PTF MF60250 for i 7.1.             *
*                 Apply LIC PTF MF60251 for i 7.2.             *
****************************************************************
                                                               
After PTFs applied, some queries with non-equal predicates      
started using a less then optimal index even though better      
indexes exists. This resulted in poor performing access plans  
been chosen.                                                    

Problem Conclusion

An enhancement made to the optimizer to allow the consideration
of more indexes for non-equal predicates that might prove to    
have additional selectivity benefits has been determined to be  
too broad.  The optimizer is scaling that enhancement back.    

Temporary Fix

                       *********                                
                       * HIPER *                                
                       *********                                

Comments

Circumvention


PTFs Available

R710 MF60115 PTF Cover Letter   5317
R720 MF60251 PTF Cover Letter   5310

Affected Modules

         
         

Affected Publications

Summary Information

Status............................................ CLOSED PER
HIPER........................................... Yes
Component.................................. 9400DG3DBMF6
Failing Module.......................... RCHMGR
Reported Release................... R710
Duplicate Of..............................




System i Support

IBM disclaims all warranties, whether express or implied, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose. By furnishing this document, IBM grants no licenses to any related patents or copyrights. Copyright © 1996,1997,1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017 IBM Corporation. Any trademarks and product or brand names referenced in this document are the property of their respective owners. Consult the Terms of use link for trademark information

[{"Business Unit":{"code":"BU054","label":"Systems w\/TPS"},"Product":{"code":"SG15Q","label":"APARs - OS\/400 General"},"Component":"","ARM Category":[],"Platform":[{"code":"PF012","label":"IBM i"}],"Version":"V7R1M0;V7R2M0","Edition":"","Line of Business":{"code":"","label":""}},{"Business Unit":{"code":"BU054","label":"Systems w\/TPS"},"Product":{"code":"SG16C","label":"APARs - IBM i 7.1 environment"},"Component":"","ARM Category":[],"Platform":[{"code":"PF012","label":"IBM i"}],"Version":"V7R1M0;V7R2M0","Edition":"","Line of Business":{"code":"","label":""}},{"Business Unit":{"code":"BU054","label":"Systems w\/TPS"},"Product":{"code":"SG16E","label":"APARs - IBM i 7.2 environment"},"Component":"","ARM Category":[],"Platform":[{"code":"PF012","label":"IBM i"}],"Version":"V7R1M0;V7R2M0","Edition":"","Line of Business":{"code":"","label":""}}]

Document Information

Modified date:
08 September 2017