How do Hibernate dirty checking, flush, and transaction commit relate?

Explains how managed changes become SQL at flush and why flush is not the same as a durable commit.

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TL;DR

Hibernate keeps track of managed entity state and detects changes, usually by comparing it with a snapshot or enhanced tracking data. At flush, it translates pending inserts, updates, and deletes into SQL so the database state is synchronized with the persistence context. Flush commonly happens before transaction commit and can also happen before a query whose result could depend on pending changes. A successful flush is not a commit; the transaction can still roll back.

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Dirty checking, automatic updates, flush timing, query synchronization, constraints, and commit semantics.

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Overview
Changing a managed object records intent in memory; flush synchronizes that intent with SQL, and commit completes the transaction.
Hibernate keeps track of managed entity state and detects changes, usually by comparing it with a snapshot or enhanced tracking data. At flush, it translates pending inserts, updates, and deletes into SQL so the database state is synchronized with the persistence context. Flush commonly happens before transaction commit and can also happen before a query whose result could depend on pending changes. A successful flush is not a commit; the transaction can still roll back.
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Constraint violations may therefore appear at an explicit flush, during a later query, or at commit rather than on the setter that caused the invalid state. Calling save repeatedly does not guarantee one immediate SQL statement per call, and Hibernate may order work. I use explicit flush only when the application needs database feedback or ordering before the natural boundary. Flushing inside every repository call usually adds round trips and weakens batching without improving correctness.

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Treating flush as a durable commit.
Assuming setters immediately execute update SQL.
Flushing after every entity without a requirement.

How do Hibernate dirty checking, flush, and transaction commit relate?

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