Limited supportBMC provides limited support for this version of the product. As a result, BMC no longer accepts comments in this space. If you encounter problems with the product version or the space, contact BMC Support.BMC recommends upgrading to the latest version of the product. To see documentation for that version, see UNLOAD PLUS for DB2 13.1.

Drain and lock table processing

UNLOAD PLUS can drain or lock objects, depending on certain conditions.

Important

When you are performing a partial unload (using the PART keyword or FILTERPART), the drain information in this section applies to the participating partitions.

UNLOAD PLUS locks tables only when all of the following conditions exist:

  • You are unloading a nonpartitioned table space with multiple tables.
  • The table space is not in UT status.
  • You are not unloading all tables in the table space.

In all other cases, UNLOAD PLUS drains the objects when required.

How long the drain or lock is held

The drain or lock is held throughout the entire unload process with the following exceptions:

  • For SHRLEVEL CHANGE CONSISTENT YES, the drain or lock is held throughout the XBM or SUF registration process (including quiesce).
  • For SHRLEVEL CHANGE CONSISTENT NO QUIESCE YES, the drain or lock is held throughout the quiesce process.

Controlling drain behavior

You can use the following command options to control drain behavior:

  • DRAIN_WAIT
  • RETRY
  • RETRY_DELAY
  • FORCE

If UNLOAD PLUS cannot drain all of the objects within the time period specified by DRAIN_WAIT, UNLOAD PLUS releases the drains that it has obtained so far, waits for the length of time specified in the RETRY_DELAY command option, and tries to drain the objects again. UNLOAD PLUS retries for the number of times specified in the RETRY command option. The FORCE option can change this process by enabling you to specify if and when you want to cancel any threads that might prevent a successful drain.

Important

You can also use installation options to set defaults for these command options.

Controlling lock behavior

To control lock behavior, you can use the SQLDELAY and SQLRETRY installation options. If UNLOAD PLUS cannot acquire a lock on a table, it waits for the length of time specified in the SQLDELAY option and then tries to acquire a lock again. UNLOAD PLUS retries for the number of times specified in the SQLRETRY option.

Related topics

UNLOAD-PLUS-serialization-and-concurrency

Operational-considerations

 

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