Hibernate Open Session in View: To Use or Not to Use?

Hibernate Open Session in View: A Controversial Practice

Introduction

Open Session In View (OSIV) is a Hibernate feature that allows the Hibernate session to remain open during the request-response cycle. This practice has been a topic of debate in the Java community, with some advocating for its convenience while others question its drawbacks.

Issues with OSIV

OSIV presents several challenges:

• Inconsistent Transaction Handling: OSIV keeps the session open indefinitely, bypassing the typical transaction lifecycle. This can lead to unintended consequences, such as data consistency issues.
• Database Performance Degradation: Keeping a session open puts pressure on the database, as any additional statements executed during the response processing (e.g., lazy association initialization) are issued in auto-commit mode.
• Blurred Layer Separation: OSIV blurs the separation of concerns between the business layer and the UI rendering phase, making it difficult to test and maintain the application.
• Increased Connection Lease Time: The session can be held open for an extended period, limiting the database connection pool's resources.

Alternative Strategies

To avoid these issues, developers can employ alternative strategies:

• Explicitly Initialize Lazy Associations: Initialize lazy associations in the service layer using Join Fetch or FetchMode.SUBSELECT.
• Create Separate DAO Queries: Write specific DAO queries for the UI layer that are tailored to fetch only the necessary associations.
• Use View Projections: Create projections that return only the essential fields needed for the UI rather than complete entities.
• Use FetchMode.LAZY and EAGER Loading: Configure FetchMode.LAZY for entities not immediately required and FetchMode.EAGER for associations that must be loaded upfront.

Disabling OSIV in Spring Boot

Spring Boot enables OSIV by default. To disable it, set the following property in the application.properties file:

spring.jpa.open-in-view=false

This setting ensures that the Hibernate session is closed after each service layer transaction, preventing the potential drawbacks associated with OSIV.

The above is the detailed content of Hibernate Open Session in View: To Use or Not to Use?. For more information, please follow other related articles on the PHP Chinese website!