How to Achieve Lazy Loading of LOBs in Hibernate with Spring?

Spring Hibernate Blob Lazy Loading

Lazy loading in Hibernate enables deferred retrieval of data, reducing memory consumption and improving performance. However, some users have encountered issues with lazy loading of LOBs (Large Object Binary) in Hibernate.

In a typical Hibernate configuration with MySQL, TOMCAT, Spring, and Hibernate, entities annotated with @Lob should have lazy fetching by default. However, some users report that this behavior is inconsistent across different drivers and databases.

One potential issue is related to bytecode instrumentation. Using frameworks like Javaassist or cglib for bytecode manipulation can affect how Hibernate interprets lazy loading annotations.

In cases where lazy loading of LOBs fails, the recommended workaround is to use one-to-one mappings as a placeholder for the LOB fields. This involves creating separate classes that refer to the same table and primary key, but only contain the necessary LOB fields as properties. The mappings should be configured as fetch="select" and lazy="true". This ensures that the LOB data is retrieved only when explicitly requested.

By implementing this solution, you can effectively enable lazy loading of LOBs while addressing potential compatibility issues or limitations in the lazy loading mechanism of Hibernate.

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