XBM and SUF considerations
To enhance performance, REORG PLUS uses several features of
XBM
or
SUF
during portions of the reorganization process.
If you have installed the required version of XBM or SUF, REORG PLUS can use the following XBM or SUF functions:
- Software snapshot functions for a SHRLEVEL CHANGE reorganization
- Instant Snapshot technology for the nonpartitioned indexes during a SHRLEVEL REFERENCE or SHRLEVEL CHANGE partial table space reorganization
- zIIP processing
XBM and SUF are licensed, installed, and maintained separately from REORG PLUS. You can use either XBM or SUF, depending on the license that you have obtained:
- A license for the full version of the XBM product authorizes you to use all XBM features.
- A license for SUF authorizes you to use only the snapshot and zIIP-processing features of XBM.
For more information, see the EXTENDED BUFFER MANAGER for Db2 documentation.
Using XBM or SUF with nonpartitioned indexes
For a SHRLEVEL REFERENCE or SHRLEVEL CHANGE partial table space reorganization, REORG PLUS can use Instant Snapshot technology to copy each nonpartitioned index to a staging data set.
Instant Snapshot copies the entire nonpartitioned index in one operation, thus eliminating the multiple reads and writes of the traditional copy method (for SHRLEVEL REFERENCE) and the software snapshots (for SHRLEVEL CHANGE).
For the steps to take to use Instant Snapshot technology in this case, see Instant-Snapshot-with-nonpartitioned-indexes.
Using XBM or SUF with SHRLEVEL CHANGE
By using the software snapshot functions of XBM or SUF when performing a SHRLEVEL CHANGE reorganization, REORG PLUS can reorganize and apply the log records to a consistent image of the data while the data is available for RW operations.
Using XBM or SUF also allows you to monitor and alter the execution of the reorganization by using the MVS console or the XBM Utility Monitor.
For REORG PLUS processing, software snapshots are most efficient and require the least amount of time to register. For proper REORG PLUS operation, ensure that XBM or SUF is configured with sufficient cache for the number of concurrent snapshots and the level of Db2 update activity at your site. For specific cache configuration information, see the EXTENDED BUFFER MANAGER for Db2 documentation.
REORG PLUS does not use the traditional hardware snapshot functions of XBM or SUF, even if XBM or SUF is configured to take hardware snapshots.
For the steps to take to run a SHRLEVEL CHANGE reorganization, see Running-a-SHRLEVEL-CHANGE-reorganization.