A beginner’s guide to JPA/Hibernate flush strategies

Vlad Mihalcea

Introduction

In my previous post I introduced the entity state transitionsObject-relational mapping paradigm.

All managed entity state transitions are translated to associated database statements when the current Persistence Context gets flushed. Hibernate’s flush behavior is not always as obvious as one might think.

Write-behind

Hibernate tries to defer the Persistence Context flushing up until the last possible moment. This strategy has been traditionally known as transactional write-behind.

The write-behind is more related to Hibernate flushing rather than any logical or physical transaction. During a transaction, the flush may occur multiple times.

The flushed changes are visible only for the current database transaction. Until the current transaction is committed, no change is visible by other concurrent transactions.

The persistence context, also known as the first level cache, acts as a buffer between the current entity state transitions and the database.

In caching theory, the write-behind synchronization…

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