Should You Use Spring Boot\'s `spring.jpa.open-in-view=true`?

"Spring Boot's spring.jpa.open-in-view=true: Unveiling the OSIV Anti-Pattern and Its Implications

Understanding Open Session in View (OSIV)

The spring.jpa.open-in-view property in Spring Boot documentation is a flag that controls whether Hibernate's session will remain open during the servlet request handling phase. By default, this property is set to true, activating the OSIV pattern.

Consequences of Using OSIV

The OSIV pattern poses several significant downsides:

• Database Performance Degradation: Auto-commit mode is used during the rendering phase, exerting strain on the database server.
• Confusion of Concerns: Database statements are generated both by the business logic and the UI, complicating integration testing and code maintenance.
• N 1 Query Problems: The UI's ability to traverse associations can trigger N 1 query issues.
• Connection Congestion: Keeping database connections open throughout the rendering phase extends lease times and hinders concurrency.

Disabling OSIV in Spring Boot

To disable OSIV and ensure optimal performance and scalability:

• Explicitly set spring.jpa.open-in-view: true=false in the application.properties configuration file.
• Spring Boot issues a warning when OSIV is enabled by default, starting from version 2.0, alerting developers to the potential issue.

Handling LazyInitializationException

If OSIV is disabled, the "LazyInitializationException" may occur when the UI attempts to access lazily initialized associations. To prevent this exception:

• Use fetch join or fetch eager annotations to eagerly retrieve associated entities.
• Utilize fetch graphs or JPQL queries with JOIN FETCH clauses to select specific associated entities.
• Consider using a separate service tier or DAO for data access, allowing for tailored data fetch strategies based on the use case.

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