PH04468: INFINITE LOOP OR ABENDS0C4 DURING A LOGICAL UNLOAD WITH ORDER CLAUSE INVOLVING THE INDEX SCAN FEATURE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• (HPU 5.1 only) A logical unload with an ORDER clause and run in
  native mode can enter an infinite loop or fails with ABENDS0C4.
  
  This occurs when the following conditions are fulfilled:
  
  - The index scan feature is used by Db2 HPU, i.e. the INDESCAN
    NO option is NOT specified and an eligible index for the
    index scan feature exists
  
  - The first valid key of a page from the index involved in the
    index scan feature is a link
  
  PB54503
  

Local fix

• Reorganize the involved index for an immediate solution or
  disable the index scan feature by specifying the
  INDESCAN NO option which might decrease the performance of the
  sort phase.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * Users of High Performance Unload                             *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * PH04458:                                                     *
  * The Db2 HPU implementation of the DISCOVER feature to be     *
  * used with Tool Customizer (TCz) should allow to retrieve     *
  * data from a the parmlib content generated at the same Db2    *
  * HPU version.                                                 *
  * When such an attempt is done, the following error message is *
  * issued INZDSC13E : Discover version 5.1.0 cannot work with   *
  * an old PARMLIB from version 5.1.0 and the DISCOVER fails.    *
  *                                                              *
  * PH04468:                                                     *
  * Fix 1 - Support of LBI (large block interface) for output    *
  * files                                                        *
  * Fix 2 - A logical unload with an ORDER clause and run in     *
  * native mode can enter an infinite loop or fails with         *
  * ABENDS0C4.                                                   *
  * This occurs when the following conditions are fulfilled:     *
  * -The index scan feature is used by Db2 HPU, i.e. the         *
  * INDESCAN NO option is NOT specified and an eligible index    *
  * for the index scan feature exists                            *
  * - The first valid key of a page from the index involved in   *
  * the index scan feature is a link                             *
  *                                                              *
  * PH05422:                                                     *
  * Fix 1 - A syntax error occurs whenever UNIT or TAPEUNIT      *
  * option specify a unit name containing an hyphen (-).         *
  * For example, with the following statement:                   *
  * TEMPLATE AB DSN PREFIX.&DB..&TS..&UQ..C&PART. UNIT 3590-1    *
  * STACK YES  DATACLAS LBI                                      *
  * the following syntax error message is issued.                *
  * INZU039E FATAL SYNTAX ERROR BEFORE LINE 4 COLUMN 60          *
  * With a statement containing:                                 *
  * GLOBAL  SORTUTIL SORT MAXSORT 30 ZIIP 0,FORCE                *
  * TAPEUNIT(3490(2), 3590-1(2));                                *
  * error messages as follows are issued:                        *
  * INZU097E SYNTAX ERROR - UNRECOGNIZED ELEMENT -  FOR GLOBAL   *
  * BLOCK.                                                       *
  * INZU039E FATAL SYNTAX ERROR BEFORE LINE 10 COLUMN 27         *
  * Fix 2 - Any logical unload requesting to unload compressed   *
  * LOB data in native mode ends with ABENDU1132 with reason     *
  * code 20.                                                     *
  * Fix 3 - The INDEXSCAN feature is less efficient than         *
  * expected when the multiple keys index used by the INDEXSCAN  *
  * feature has a key that references only a record which is     *
  * actually a link.                                             *
  * This only impacts the performance of logical unload run in   *
  * native mode with an ORDER clause eligible for the INDEXSCAN  *
  * feature.                                                     *
  *                                                              *
  * PH05424:                                                     *
  * When a native unload involves LOB or XML data and no         *
  * consistency matter requires neither to QUIESCE (e.g. by the  *
  * DB2 HPU QUIESCE YES option) the object nor to prevent any    *
  * update of the LOB or XML data during the unload (e.g. by the *
  * DB2 HPU LOCK YES option), the unload might fail (with an     *
  * ABENDU1132) because of the lack of consistency between the   *
  * underlying datasets which prevent to correctly retrieve the  *
  * LOB or XML data associated with a given base row.            *
  * DB2 HPU should be able to handle this kind of situation by   *
  * skipping the unload of the LOB or XML data but keeping the   *
  * base row and issuing a warning message explaining the        *
  * LOB/XML value was skipped due to inconsistency between the   *
  * base and LOB tablespaces.                                    *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Apply the PTF for problem resolution                         *
  ****************************************************************
  

Problem conclusion

• Code has been changed to fix this problem
  

Temporary fix

• PH04468:
  Fix 2 - Reorganize the involved index for an immediate solution
  or disable the index scan feature by specifying the INDESCAN NO
  option which might decrease the performance of the sort phase.
  
  PH05422:
  Fix 1 - None unless unit name with no hyphen can be substituted
  to the current one.
  Fix 2 - Use the SQL mode by specifying DB2 FORCE.
  Fix 3 - Consider reorganizing the index involved in the
  indexscan feature if the issue drastically affects the unload
  job performance.
  

Comments

APAR Information

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

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

  UI60061

Modules/Macros

• INZTDSC  INZ$$PRM INZCRXSM INZCRXSQ INZUTILK INZTVAR
  

Fix information

• Fixed component name

  DB2 HI PERF UNL

• Fixed component ID

  5697F4400

Applicable component levels

• R510 PSY UI60061

     UP18/12/07 P F812

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.