DB2 Developers Guide (5th Edition)

Dynamic Cursor Pre- Open

In certain situations, DB2 automatically adds an OPEN cursor request to the PREPARE statement. By anticipating that a cursor is to be opened and doing so, DB2 optimizes performance by avoiding VTAM overhead.

To take advantage of dynamic cursor pre-open, the statement being prepared must be a SELECT statement, no parameter markers can be used, and the connection must be a DRDA connection.