Technical Blog Post
Abstract
New DB2 Isolation level - Currently Committed for users of IBM Tivoli service management products
Body
However, unlike DB2, the default locking for Oracle does not lock the reader. As a result, applications originated from Oracle (like IBM Tivoli service management products) will likely run into long lock waits and much higher deadlocks while moving to DB2.
Starting from version 9.7, DB2 introduces a new isolation level semantic called "Currently Committed” that allows DB2 locking to generally work as Oracle does. This means that applications can work with both DB2 and Oracle databases without having to code different logic. Under this "Currently Committed" semantics, only committed data is returned, as was in Cursor Stability, but now readers do not wait for writers to release the locks. Instead readers return data that is based on the currently committed version. See the following table for the Currently Committed locking behavior:
UID
ibm11134705