Manageability enhancements

The Db2 11.5.4 release provides enhancements that make it easier to manage Db2 environments, minimize the total cost of ownership (TCO), reduce the impact of performing system management tasks, and extend the capabilities of the autonomic features introduced in previous releases.

Attention: The enhancements in this topic are included in the Db2 11.5.4 mod pack release, which is available for the following products:

Db2 on-premises
The single container deployments of Db2 Warehouse and IBM Integrated Analytics System (IIAS)
The container micro-service deployment of Db2 on Red Hat OpenShift

The following table lists manageability enhancements that have been added to the Db2 11.5.4 release:

Table 1. Manageability enhancements in 11.5.4
Enhancement	Description
Ability to block REORG-recommended ALTER TABLE actions that would put the table into reorg pending state	Users can disallow ALTER TABLE operations that place a table into a reorg pending state, preventing the unintentional loss of full access to a table. For more information, refer to DB2_BLOCK_REORG_PENDING.
Alternative handling of table space error during database recovery, including HADR standby	Users can specify not to use the default handling when database recovery encounters a table space in an invalid or error state. The default handling is to continue the recovery on other valid table spaces and leave the invalid table space to be recovered in a future recovery operation. This default behavior is preferable when the affected table space is only a small portion of the database and most applications can function with the valid table spaces. Users can specify a different behavior by setting the new DB2_FAIL_RECOVERY_ON_TABLESPACE_ERROR registry variable to ROLLFORWARD. For more information on this new registry variable, refer to DB2_FAIL_RECOVERY_ON_TABLESPACE_ERROR.
Ability to specify the query optimizer version	The DB2_OPTIMIZER_VERSION registry variable can be used to have the query optimizer run at a previous Db2 version in order to disable query optimizations introduced between that version and the current Db2 version, to avoid performance regressions due to inappropriate access plan changes.