PI53169: POOR SQL PERFORMANCE WHEN RANGE LIST ACCESS IS USED AND PTF UI22717 IS APPLIED 15/11/25 PTF PECHANGE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Poor SQL performance when range list access is used and
  PTF UI22717 is applied .
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of DB2 10 and DB2 11 for z/OS      *
  *                 who have queries eligible for range list     *
  *                 access and have PI15740 applied              *
  *                 (UI22717 on DB2 10; UI22718 on DB2 11)       *
  ****************************************************************
  * PROBLEM DESCRIPTION: Poor query performance can occur for a  *
  *                      query using range list access when the  *
  *                      query contains both BETWEEN and range   *
  *                      predicates on the same column           *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  Poor query performance can occur after PI15740 is applied for a
  query using range list access when the query contains both
  BETWEEN and range predicates on the same column.  The range
  predicate can be chosen as the best matching predicate even
  when the BETWEEN predicate provides better filtering.
  The difference in predicates chosen as best-matching is not
  distinguishable from the PLAN_TABLE after an Explain.
  
  Additional Keywords:
  SQLPERFORMANCE SQLACCESSPATH RANGELIST SQLBETWEEN
  SQLLT SQLGT SQLLE SQLGE
  

Problem conclusion

• DB2 code is updated to correct the selection of best matching
  predicates in the situation described above.  This can lead to
  better query performance.
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

  UI34917 UI34918

Modules/Macros

• DSNXOGBM
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• RA10 PSY UI34917

     UP16/02/16 P F602 Ø

• RB10 PSY UI34918

     UP16/02/16 P F602 Ø

Fix is available

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