PI17400: Performance problem with multi fact query using Dynamic Query Mode (DQM)

APAR status

• Closed as program error.

Error description

• Creating a multi-fact query using DQM in 10.2.1 generates a FULL
  OUTER JOIN with an IS NOT DISTINCT clause. This is causing a
  huge performance issue.??e.g. the generated Cognos SQL will
  contain the following :??FROM FS1 FULL OUTER JOIN FS2?ON
  FS1.CURRENT_YEAR IS NOT DISTINCT FROM FS2.CURRENT_YEAR??and the
  Native SQL will contain :??FROM "FS1" FULL OUTER JOIN "FS2" ON
  "FS1"."CURRENT_YEAR" = "FS2"."CURRENT_YEAR" OR
  ("FS1"."CURRENT_YEAR" IS NULL AND "FS2"."CURRENT_YEAR" IS
  NULL)??If the SQL is run without the OR ("FS1"."CURRENT_YEAR" IS
  NULL AND "FS2"."CURRENT_YEAR" IS NULL) clause then the query
  completes in 3 seconds but with this clause in place, it times
  out after 10 minutes.??In previous versions the IS NOT DISTINCT
  clause was not generated and there was no performance problem.
  ??
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All Users                                                    *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See error description.                                       *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to IBM Cognos Business Intelligence 10.2.1 Fix Pack  *
  * 4                                                            *
  ****************************************************************
  

Problem conclusion

• Code Fix
  

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:

Fix information

• Fixed component name

  COG FRAMEWRK MG

• Fixed component ID

  5724W12FM

Applicable component levels

• RA21 PSN

     UP