DB2 CLI allows the isolation level to be set at the statement level, (however, we recommend that the isolation level be set at the connection level). The isolation level determines the level of concurrency possible, and the level of locking required to execute the statement.
Resources associated with statement handles can be better utilized by DB2 CLI if statements are set to the required isolation level, rather than leaving all statements at the default isolation level. This should only be attempted with a thorough understanding of the locking and isolation levels of the connected DBMS. Refer to the SQL Reference for a complete discussion of isolation levels and their effect.
Applications should use the minimum isolation level possible to maximize concurrency.