DDL MATERIALIZATION field (DDL_MATERIALIZATION subsystem parameter)

This subsystem parameter is new in Db2 12. It can be set at any function level, but it takes effect only after activation of function level 500 or higher.

It applies only for ALTER TABLE statements that specify the ALTER COLUMN and SET DATA TYPE keywords to change the data type, length, precision, or scale of a column. The column must be in a table in a universal table space, or in a table space that has an unmaterialized pending alter to convert it to a universal table space. The data sets for the table space must already be created.

This option is ignored in other cases, such as when alter operations must be executed as a pending alteration or must be executed as an immediate alteration.

This option specifies whether object definition changes are executed as immediate or pending alterations:

1 (ALWAYS_IMMEDIATE)

For applicable requests, changes are materialized at the time that the request is executed, and the containing table space is placed in AREO* or REORP status. If there are any existing unmaterialized pending changes, the request fails.

2 (ALWAYS_PENDING)

For applicable requests, changes are not materialized at the time that the request is executed, and the affected objects are available until it is convenient to implement the changes. The containing table space is placed in AREOR status. If any immediate options are specified in the same statement, the change request fails. If any subsequent immediate changes are executed before a pending change is materialized, those subsequent immediate changes fail.