Conditional restart

A conditional restart is a Db2 restart that is directed by a user-defined conditional restart control record (CRCR).

If you want to skip some portion of the log processing during Db2 restart, you can use a conditional restart. However, if a conditional restart skips any database change log records, data in the associated objects becomes inconsistent, and any attempt to process them for normal operations might cause unpredictable results. The only operations that can safely be performed on the objects are recovery to a prior point of consistency, total replacement, or dropping.

In unusual cases, you might choose to make inconsistent objects available for use without recovering them. For example, the only inconsistent object might be a table space that is dropped as soon as Db2 is restarted, or the Db2 subsystem might be used only for testing application programs that are still under development. In cases like those, where data consistency is not critical, normal recovery operations can be partially or fully bypassed by using conditional restart control records in the BSDS.

Restart considerations for identity columns

Cold starts and conditional restarts that skip forward recovery can cause additional data inconsistency within identity columns and sequence objects. After such restarts, Db2 might assign duplicate identity column values and create gaps in identity column sequences.