Transactional Isolation And Propagation

Propagation

Defines how transactions relate to each other. Common options:

• Required: Code will always run in a transaction. Creates a new transaction or reuses one if available.
• Requires_new: Code will always run in a new transaction. Suspends the current transaction if one exists.

Isolation

Defines the data contract between transactions.

• Read Uncommitted: Allows dirty reads.
• Read Committed: Does not allow dirty reads.
• Repeatable Read: If a row is read twice in the same transaction, the result will always be the same.
• Serializable: Performs all transactions in a sequence.

The different levels have different performance characteristics in a multi-threaded application. Those who understand the dirty reads concept they are able to be select a good option.

References

• Spring Transactional Isolation & Propagation
• Spring transaction isolation level tutorial