Application behavior when running in a mixed release environment

There are special application considerations when the Db2® Mirror nodes are running on different IBM® i operating system levels.

When the operating systems levels are different across the node pair, actions initiated from the node using the higher level operating system will fail if the replication action includes an enhancement which is unique to the higher level operating system. Operations and replication actions initiated from the node using the lower level system will not fail.

This means that if the mixed release environment consists of Node A (on IBM i 7.4) and Node B (on IBM i 7.5), replicated objects cannot use software enhancements that exist only on IBM i 7.5.

Consider the following example. The database file named SALES is a replicated object. On the IBM i 7.5 node, the Database Engineer (DBE) decides to protect the SALES file from being accidentally dropped by using the RESTRICT ON DROP feature.

ALTER TABLE sales ADD RESTRICT ON DROP;

The attempt to execute this SQL statement will fail, because the RESTRICT ON DROP support only exists on IBM i 7.5. The DBE must wait until both nodes are running with IBM i 7.5 before establishing RESTRICT ON DROP on database files that are being replicated by Db2 Mirror.

When the replication action is initiated from the higher level node and the action is disallowed because it includes a software enhancement unique to the node at the higher level, the operation fails as follows:

SQL statements fail with SQLCODE = -7061 and SQLSTATE = '55019' (reason code 1)
CL commands fail with either CPFC922 (reason code 1), and possibly also CPF32AF (reason code 1)