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IT33537: UNEXPECTED INTERNAL ERROR 172 RUNNING MERGE STATEMENT USING SUBQUERIES

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APAR status

  • Closed as program error.

Error description

  • A MERGE statement involving multiple subqueries may fail with
    error 959 / 172 when a join condition exists that connects the
    two subqueries.
    
    An example statement:
    
    MERGE INTO target t USING
    ( SELECT mnum, cref FROM source ) x
    ON t.num = x.mnum
    WHEN MATCHED THEN UPDATE
      SET code =
      (SELECT code FROM ref WHERE cref = x.cref);
    
    An Assert Failure is generated which includes a thread stack
    similar to:
    
    ld_newvals_in2tmpbuf
    subqcache_find
    chkrmk
    exsubq
    ev_cb
    new_eval
    eval_projection_list
    dodmlrow
    process_upsert
    upsert_next
    doupsert
    excommand
    sq_execute
    sqmain
    

Local fix

  • a workaround can be using a view for the target table:
    
    create view vt as (select num, code from target);
    merge into vt t using
    ...
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * Users of Informix Server prior to 12.10.xC15 and 14.10.xC5.  *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to Informix Server 12.10.xC15 (when available) or    *
    * 14.10.xC5.                                                   *
    ****************************************************************
    

Problem conclusion

  • Fixed in Informix Server 12.10.xC15 and 14.10.xC5.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT33537

  • Reported component name

    INFORMIX SERVER

  • Reported component ID

    5725A3900

  • Reported release

    C10

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2020-07-14

  • Closed date

    2021-01-18

  • Last modified date

    2021-01-18

  • 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

    INFORMIX SERVER

  • Fixed component ID

    5725A3900

Applicable component levels

[{"Line of Business":{"code":"LOB10","label":"Data and AI"},"Business Unit":{"code":"BU029","label":"Software"},"Product":{"code":"SSGU8G","label":"Informix Servers"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"C10"}]

Document Information

Modified date:
19 January 2021