Unidirectional @OneToMany relationships are notoriously inefficient. When a child entity is added or removed from a unidirectional list, Hibernate often deletes all existing rows in the child table and reinstates them one by one to preserve collection ordering.
A bank’s quarterly report generation took 6 hours. The code looped over millions of records, causing massive JVM heap pressure and GC pauses. By switching to and JDBC batching (Chapter 12 of the PDF), the runtime dropped to 25 minutes. High-performance Java Persistence.pdf
JPA and Hibernate are built on top of JDBC. If your underlying JDBC configuration is sub-optimal, no amount of application-level caching or ORM tuning will save your performance. Connection Pooling Configuration The code looped over millions of records, causing
The e-book version is available on and Leanpub in multiple formats, including PDF , EPUB, and MOBI (for Kindle). For the paperback version, it is printed on demand by Amazon and can be purchased on Amazon's regional sites like Amazon.com. If your underlying JDBC configuration is sub-optimal, no
Database connections are held open for the entire duration of a transaction. If your transaction performs long-running tasks like calling external HTTP REST APIs, parsing massive files, or processing heavy business logic, your connection pool will quickly starve.