DB2 restricts the max row length to be less than the page size, even if the max length is never reached in practice. The "table per class hierarchy" mapping strategy is particularly affected by this restriction, as the combined columns of all subclasses easily add up to an excessive length. In the case of the JBPM_LOG table, the required page size under DB2 is 32KB.

For this reason it is desirable that end users can easily switch from the on-row type VARCHAR to the off-row type TEXT/CLOB. Such a switch would benefit other databases as well, provided it is possible for users to upgrade their existing database schema. One situation where switching would be helpful is JBPM-2057.