PI73173: ELAPSED TIME DEGREDATION IN REBUILD INDEX WITH DB2 SORT FOR Z/OSWHEN BUILDING MULTIPLE INDEXES ON A PARTITIONED TABLE SPACE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• REBUILD INDEX started multiple unload tasks to unload from
  multiple partitions at the same time but when only one unload
  task actually processed records, it caused the communication
  with Db2 Sort to slow down significantly.
  
  Additional Keywords:
  DB2SORT/K
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All DB2 12 for z/OS CHECK INDEX, REBUILD INDEX, LOAD DATA,   *
  * and REORG TABLESPACE users with DB2 Sort for z/OS.           *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * Degraded elapsed time performance when running CHECK INDEX   *
  * or REBUILD INDEX utilities with DB2 Sort for multiple        *
  * indexes of a partitioned table space with data unloaded in a *
  * single unload task only when multiple unload tasks were      *
  * originally started as identified by multiple messages        *
  * DSNU555I UNLOAD PHASE STATISTICS - NUMBER OF RECORDS         *
  * PROCESSED=0.                                                 *
  *                                                              *
  * Degraded elapsed time for LOAD DATA with partition           *
  * parallelism by multiple INDDN specifications when only a     *
  * single input data set contains data.                         *
  *                                                              *
  * Degraded elapsed time for REORG with partition unload/reload *
  * parallelism when only a single partition contains data rows. *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Apply corrective PTF when available                          *
  ****************************************************************
  Processing parallelism between DB2 and DB2 Sort for these cases
  was intended to be realized by data being provided to sort from
  more than one task. If only a single task was providing records
  to DB2 Sort then no more parallelism could be achieved and
  execution was done serially.
  

Problem conclusion

• Code has been changed to allow parallel execution of DB2 and DB2
  Sort by using multiple data transfer buffers for each input
  task.
  

Temporary fix

Comments

APAR Information

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

  PI73169

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

  UI44663

Modules/Macros

• DSNUCRIB DSNUKPIK DSNURPCT DSNURPIB DSNUGSRP DSNUGALC DSNUGLSR
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• RC10 PSY UI44663

     UP17/03/03 P F703

Fix is available

• Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.