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Building Scalable Applications with Thymeleaf and Spring Boot

Open Session in View

Get introduced to Open Session in View.

We'll cover the following...

What is OSIV?

If we observe the logging output of the Spring Boot application, we will see this warning:

Shell
2020-09-08 17:06:32.095 WARN 75541 --- [ main]
JpaBaseConfiguration$JpaWebConfiguration : spring.jpa.open-in-view is enabled by 
default. Therefore, database queries may be performed during view rendering.
Explicitly configure spring.jpa.open-in-view to disable this warning.

By default, Spring Boot has Open Session In View (OSIV) enabled. However, this is considered to be an antipattern by many.

Why is OSIV an anti-pattern?

To answer that question, let’s first explain what Open Session In View does. Put simply:

The Session is what JPA/Hibernate needs to make the database work.

When a controller calls a service, a transaction is started and spans all database calls that the service does (via a repository). The transaction/session is closed when the service returns the deserialized objects to the controller. As a performance optimization, some references of a returned entity are lazy-loaded. ...