The best way to map a @OneToOne relationship with JPA and Hibernate

Introduction

There are many ways you can map a one-to-one relationship with Hibernate. In this post, I’m going to demonstrate which mapping is the most efficient one from a database perspective.

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The best way to detect database connection leaks

Introduction

Database connections are not free, and that’s the reason for using a connection pooling solution in the first place. However, the connection pool alone does not solve every issue associated to managing database connections. The application developer must make sure that every Connection is closed when no longer needed. Behind the scenes, the connection pool gives a logical transaction which, when being closed, it returns back to the pool so that it can be further reused by other concurrent transactions.

A connection leak happens when a connection is acquired without ever being closed.

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How to lazy load entity properties with Hibernate

Introduction

One of my readers bumped into the JSON mapping post and asked me if we can fetch the JSON properties lazily. This post demonstrates how easily this can be done when using Hibernate as a JPA provider.

As I previously explained, EAGER fetching is a code smell and loading associations eagerly is very detriment to application performance. However, it’s not just associations that we must be careful about. Basic entity properties may also cause performance issues as well. In this post, I’m going to show you how you can fetch entity properties lazily.

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14 High-Performance Java Persistence Tips

Introduction

A high-performance data access layer requires a lot of knowledge about database internals, JDBC, JPA, Hibernate, and this post summarizes some of the most important techniques you can use to optimize your enterprise application.

1. SQL statement logging

If you’re using a framework that generates statements on your behalf, you should always validate each statement effectiveness and efficiency. A testing-time assertion mechanism is even better because you can catch N+1 query problems even before you commit your code.

2. Connection management

Database connections are expensive, therefore you should always use a connection pooling mechanism.

Because the number of connections is given by the capabilities of the underlying database cluster, you need to release connections as fast as possible.

In performance tuning, you always have to measure, and setting the right pool size is no different. A tool like FlexyPool can help you find the right size even after you deployed your application into production.

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