TIBCO BusinessEvents® Extreme transactions support the following transaction isolation levels for objects:
Serializable - modifications are only visible outside of the current transaction when it commits. Transaction read locks are taken for the duration of the transaction to ensure read consistency. All writes are blocked while a transaction read lock is held. This is the default transaction isolation level.
Read Committed - Snapshot - modifications are only visible outside of the current transaction when it commits. Snapshots are taken from the last committed transaction (i.e. It is not a dirty read) to ensure read consistency during a transaction. No transaction read locks are taken during the transaction allowing object modifications to occur while reading an object. Read consistency is provided by the snapshot data across all fields in an object.
Both object isolation levels, serializable and read committed - snapshot, provide consistent, or repeatable reads during a transaction on the same node. This means that the same object field read multiple times in a transaction returns the same value. Read consistency is not guaranteed across nodes. See the section called “State conflicts” for details on how data inconsistencies are handled.
Extents always use this transaction isolation level: