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IC71723: SIGSEGV IN SQLRA_UNCONCENTRATE_STATEMENT() WHEN STATEMENT CONCEN TRATOR IS DISABLED AND STATEMENT IS ISSUED IN 2 CONNECTIONS

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APAR status

  • Closed as program error.

Error description

  • A segmentation fault trap can be generated in
    sqlra_unconcentrate_statement() function call when a statement
    with literals was previously concentrated in the dynamic SQL
    cache.
    
      Statement concentrate function can be dynamically enabled by
    the following a database configuration paramenter or other
    statement attributes like JDBC driver property ;
    
          DB CFG parameter STMT_CONC = LITERALS
          JDBC property statementConcentrator =
    DB2BaseDataSource.STATEMENT_CONCENTRATOR_WITH_LITERALS
    
      If statement concentrator is now disabled (either for the
    database or the statement) and this same statement (with the
    same literal values) is now issued concurrently by 2 (or more
    connections), then the segmentation fault can occur in one of
    the DB2 agents.
    
      The following is a sample stack trace on this issue.
    
          sqlra_unconcentrate_statement
          sqlra_get_var
          sqlrr_execute_immediate
          sqlrr_execimmd
          sqljs_ddm_excsqlimm
    

Local fix

  • - Disable statement concentrator, recycle database, and do not
    use statement concentrator.
      or
      - Do not disable statement concentrator with an active
    database when it has been enabled, if there is a possibility of
    the same statement being issued from multiple connections
    concurrently.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * statement concentrator user                                  *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * SIGSEGV comes up in sqlra_unconcentrate_statement() when the *
    * corresponding statements are simultaneously unconcentrated   *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to db2 Version 9.7 FixPak 4                          *
    ****************************************************************
    

Problem conclusion

  • Problem was the first fixed in Version 9.7 FixPak 4
    

Temporary fix

Comments

APAR Information

  • APAR number

    IC71723

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    970

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2010-10-06

  • Closed date

    2011-05-12

  • Last modified date

    2011-05-12

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

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

    IC73635

Fix information

  • Fixed component name

    DB2 FOR LUW

  • Fixed component ID

    DB2FORLUW

Applicable component levels

  • R970 PSN

       UP



Document information

More support for: DB2 for Linux, UNIX and Windows

Software version: 9.7

Reference #: IC71723

Modified date: 12 May 2011