PM51097: ABEND0C4 RC38 DSNXEXPL +216A ON DYNAMIC EXPLAIN PLAN

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• After previously executing a dynamic SQL EXPLAIN STMTCACHE
  statement, a dynamic SQL EXPLAIN PLAN FOR explainable-stmt
  failed with the following abend:
    ABEND0C4 RC00000038 DSNXEXPL +216A
  
  Additional Keywords: SQLDYNSTMTCACHE SQLEXPLAIN
  

Local fix

• N/A
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All DB2 users of dyn SQL EXPLAIN STMTCACHE   *
  ****************************************************************
  * PROBLEM DESCRIPTION: After a dynamic SQL EXPLAIN STMTCACHE   *
  *                      statement, a later dyn SQL EXPLAIN PLAN *
  *                      statement fails with the following DB2  *
  *                      application abend:                      *
  *                                                              *
  *                       ABEND0C4 RC00000038 DSNXEXPL +2nnn     *
  *                                                              *
  *                      Other unexpected DSNXEXPL abends or     *
  *                      SQL EXPLAIN errors are possible on      *
  *                      that dynamic SQL EXPLAIN PLAN statement *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  User issued a dynamic SQL EXPLAIN STMTCACHE statement followed
  later by a dynamic SQL EXPLAIN PLAN / ALL statement. The dynamic
  SQL EXPLAIN PLAN statement encountered a DB2 application abend:
                                                                 .
   AB0C4 RC00000038 DSNXEXPL +2nnn
                                                                 .
  DB2 Development determined that the AB0C4 DSNXEXPL occurred only
  when using an application/tool/driver (such as DSNTEP2 , SPUFI ,
  JCC , etc.) that uses the same SQL PREPARE or EXECUTE IMMEDIATE
  statement/section to prepare different dynamic SQL statements
  and then execute them, one after the other.
  This DSNXEXPL abend occurred for the dynamic SQL EXPLAIN PLAN /
  ALL due to a residual DB2 internal flag left over from
  the previous dynamic SQL EXPLAIN STMTCACHE statement that was
  prepared using this same SQL PREPARE section.  In addition to
  performing the EXPLAIN PLAN function, DB2 also incorrectly
  attempted to do the EXPLAIN STMTCACHE function under the EXPLAIN
  PLAN statement, but the EXPLAIN STMTCACHE structures were no
  longer available of course, resulting in the DSNXEXPL ABEND0C4.
  DB2 should not have attempted to perform the EXPLAIN STMTCACHE
  because that SQL statement had completed previously and
  structures freed.
                                                                 .
  Other DSNXEXPL abends are possible, as well as, unexpected
  errors or unexpected EXPLAIN STMTCACHE behavior with the above
  described scenario.
                                                                 .
  The problem does not occur if
   - a different SQL PREPARE or EXECUTE IMMEDIATE stmt/section
     is used to prepare the two different EXPLAIN statements,
   - the order of the two dynamic EXPLAIN statements is reversed,
   - a non-EXPLAIN statement follows the dyn EXPLAIN STMTCACHE,
   - the EXPLAIN statements are static.
                                                                 .
  

Problem conclusion

• DB2 was modified to reset residual flags from a previous
  dynamic SQL EXPLAIN STMTCACHE statement, so that a follow-on
  dyn SQL EXPLAIN PLAN / ALL statement using the same SQL PREPARE
  section is not affected.
                                                                 .
  Additional search keywords: SQLEXPLAIN
  

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:

  UK73861 UK73862 UK73901

Modules/Macros

• DSNXEDP
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• RA10 PSY UK73861

     UP12/02/29 P F202

• R810 PSY UK73862

     UP12/02/29 P F202

• R910 PSY UK73901

     UP12/03/01 P F202

Fix is available

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