9.9.2. About READ_COMMITTED

READ_COMMITTED is one of two isolation modes available in JBoss Data Grid.

In JBoss Data Grid's READ_COMMITTED mode, write operations are made to copies of data rather than the data itself. A write operation blocks other data from being written, however writes do not block read operations. As a result, both READ_COMMITTED and REPEATABLE_READ modes permit read operations at any time, regardless of when write operations occur.

In READ_COMMITTED mode multiple reads of the same key within a transaction can return different results due to write operations modifying data between reads. This phenomenon is known as non-repeatable reads and is avoided in REPEATABLE_READ mode.