The correct getForUpdateString for DB2 should be "for update with rr"

see:
http://opensource.atlassian.com/projects/hibernate/browse/HB-1032

DB2 will release all locks created in a result set if the isolation level is lower than TRANSACTION_SERIALIZABLE (RR in DB2).

Locks and concurrency control in DB2:
http://publib.boulder.ibm.com/infocenter/db2help/topic/com.ibm.db2.udb.doc/admin/c0005266.htm
"
The duration of row locking varies with the isolation level being used:

• UR scans: No row locks are held unless row data is changing.

• CS scans: Row locks are only held while the cursor is positioned on the row.

• RS scans: Only qualifying row locks are held for the duration of the transaction.

• RR scans: All row locks are held for the duration of the transaction.
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