IBM Support

IT35860: forest of trees index becomes degraded following an in-place alter against columns which are not part of the index

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APAR status

  • Closed as program error.

Error description

  • If an in-place alter is performed on a table which does not
    affect the columns of a forest of trees (FOT) index it would be
    expected that the index is unchanged. However the index
    partition key descriptor will be modified in a manner such that
    it is regarded as a regular index and not a FOT type. For unique
    indexes this may allow rows with duplicate key values to be
    inserted. Furthermore queries making use of this index may not
    return all of the correct rows.
    The oncheck -cI command may only report an error when duplicate
    values exist in a unique index.

Local fix

  • Drop and recreate the FOT index. This action shall also be
    required following update to a version of Informix with a fix
    for this APAR.

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * Users of Informix Server prior to 12.10.xC14 and 14.10.xC4.  *
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    * RECOMMENDATION:                                              *
    * Upgrade to Informix Server 12.10.xC14 or 14.10.xC4.          *
    Drop and recreate the FOT index. This action is required
    following update to a version with a fix for this APAR.

Problem conclusion

  • Fixed in Informix Server 12.10.xC14 and 14.10.xC4.

Temporary fix


APAR Information

  • APAR number


  • Reported component name


  • Reported component ID


  • Reported release


  • Status


  • PE




  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date


  • Closed date


  • Last modified date


  • 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


  • Fixed component ID


Applicable component levels

[{"Line of Business":{"code":null,"label":null},"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSGU8G","label":"Informix Servers"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"C10"}]

Document Information

Modified date:
14 February 2021