The database supports a capability known as replication by which database data is mirrored on another database. In effect, the 2PC protocol is used internally to ensure the two databases remain synchronized. This use of the protocol is not made visible to TDP. As a result, unbounded delays can occur at various points which will simply appear as hangs. For example, under at least the following circumstances delays unattributed delays will occur if replication is involved in in-doubt resolution:
- When TDP is started
- When a session logs off