Vlad Mihalcea

How to map the latest child of a parent entity using Hibernate JoinFormula

Are you struggling with performance issues in your Spring, Jakarta EE, or Java EE application?

Imagine having a tool that could automatically detect performance issues in your JPA and Hibernate data access layer long before pushing a problematic change into production!

With the widespread adoption of AI agents generating code in a heartbeat, having such a tool that can watch your back and prevent performance issues during development, long before they affect production systems, can save your company a lot of money and make you a hero!

Hypersistence Optimizer is that tool, and it works with Spring Boot, Spring Framework, Jakarta EE, Java EE, Quarkus, Micronaut, or Play Framework.

So, rather than allowing performance issues to annoy your customers, you are better off preventing those issues using Hypersistence Optimizer and enjoying spending your time on the things that you love!

Introduction

In this article, I’m going to explain how the Hibernate JoinFormula annotation works and how you can use it to map the latest child of a parent entity.

As previously explained, the @JoinFormula is a very awesome annotation which allows you to customize the way you join entities beyond JPA @JoinColumn capabilities.

Read More

How does a relational database work

Are you struggling with performance issues in your Spring, Jakarta EE, or Java EE application?

Imagine having a tool that could automatically detect performance issues in your JPA and Hibernate data access layer long before pushing a problematic change into production!

With the widespread adoption of AI agents generating code in a heartbeat, having such a tool that can watch your back and prevent performance issues during development, long before they affect production systems, can save your company a lot of money and make you a hero!

Hypersistence Optimizer is that tool, and it works with Spring Boot, Spring Framework, Jakarta EE, Java EE, Quarkus, Micronaut, or Play Framework.

So, rather than allowing performance issues to annoy your customers, you are better off preventing those issues using Hypersistence Optimizer and enjoying spending your time on the things that you love!

Introduction

While doing my High-Performance Java Persistence training, I came to realize that it’s worth explaining how a relational database works, as otherwise, it is very difficult to grasp many transaction-related concepts like atomicity, durability, and checkpoints.

In this post, I’m going to give a high-level explanation of how a relational database works internally while also hinting some database-specific implementation details.

Read More

How to run integration tests at warp speed using Docker and tmpfs

Are you struggling with performance issues in your Spring, Jakarta EE, or Java EE application?

Imagine having a tool that could automatically detect performance issues in your JPA and Hibernate data access layer long before pushing a problematic change into production!

With the widespread adoption of AI agents generating code in a heartbeat, having such a tool that can watch your back and prevent performance issues during development, long before they affect production systems, can save your company a lot of money and make you a hero!

Hypersistence Optimizer is that tool, and it works with Spring Boot, Spring Framework, Jakarta EE, Java EE, Quarkus, Micronaut, or Play Framework.

So, rather than allowing performance issues to annoy your customers, you are better off preventing those issues using Hypersistence Optimizer and enjoying spending your time on the things that you love!

Introduction

In this article, I’m going to show you how to run integration tests on PostgreSQL, MySQL, MariaDB 20 times faster using Docker and mapping the data folder on tmpfs.

As previously explained, you can run database integration tests 20 times faster! The trick is to map the data directory in memory, and my previous article showed you what changes you need to do when you have a PostgreSQL or MySQL instance on your machine.

In this post, I’m going to expand the original idea, and show you how you can achieve the same goal using Docker and tmpfs.

Read More

How does database pessimistic locking interact with INSERT, UPDATE, and DELETE SQL statements

Are you struggling with performance issues in your Spring, Jakarta EE, or Java EE application?

Imagine having a tool that could automatically detect performance issues in your JPA and Hibernate data access layer long before pushing a problematic change into production!

With the widespread adoption of AI agents generating code in a heartbeat, having such a tool that can watch your back and prevent performance issues during development, long before they affect production systems, can save your company a lot of money and make you a hero!

Hypersistence Optimizer is that tool, and it works with Spring Boot, Spring Framework, Jakarta EE, Java EE, Quarkus, Micronaut, or Play Framework.

So, rather than allowing performance issues to annoy your customers, you are better off preventing those issues using Hypersistence Optimizer and enjoying spending your time on the things that you love!

Introduction

Relational database systems employ various Concurrency Control mechanisms to provide transactions with ACID property guarantees. While isolation levels are one way of choosing a given Concurrency Control mechanism, you can also use explicit locking whenever you want a finer-grained control to prevent data integrity issues.

As previously explained, there are two types of explicit locking mechanisms: pessimistic (physical) and optimistic (logical). In this post, I’m going to explain how explicit pessimistic locking interacts with non-query DML statements (e.g. insert, update, and delete).

Read More

A beginner’s guide to the Write Skew anomaly, and how it differs between 2PL and MVCC

Are you struggling with performance issues in your Spring, Jakarta EE, or Java EE application?

Imagine having a tool that could automatically detect performance issues in your JPA and Hibernate data access layer long before pushing a problematic change into production!

With the widespread adoption of AI agents generating code in a heartbeat, having such a tool that can watch your back and prevent performance issues during development, long before they affect production systems, can save your company a lot of money and make you a hero!

Hypersistence Optimizer is that tool, and it works with Spring Boot, Spring Framework, Jakarta EE, Java EE, Quarkus, Micronaut, or Play Framework.

So, rather than allowing performance issues to annoy your customers, you are better off preventing those issues using Hypersistence Optimizer and enjoying spending your time on the things that you love!

Introduction

Unlike SQL Server which, by default, relies on the 2PL (Two-Phase Locking) to implement the SQL standard isolation levels, Oracle, PostgreSQL, and MySQL InnoDB engine use MVCC (Multi-Version Concurrency Control), so handling the Write Skew anomaly can differ from one database to the other.

However, providing a truly Serializable isolation level on top of MVCC is really difficult, and, in this post, I’ll demonstrate that it’s very difficult to prevent the Write Skew anomaly without resorting to pessimistic locking.

Read More

The problem of AUTO JPA GenerationType with MySQL and Hibernate

Are you struggling with performance issues in your Spring, Jakarta EE, or Java EE application?

Imagine having a tool that could automatically detect performance issues in your JPA and Hibernate data access layer long before pushing a problematic change into production!

With the widespread adoption of AI agents generating code in a heartbeat, having such a tool that can watch your back and prevent performance issues during development, long before they affect production systems, can save your company a lot of money and make you a hero!

Hypersistence Optimizer is that tool, and it works with Spring Boot, Spring Framework, Jakarta EE, Java EE, Quarkus, Micronaut, or Play Framework.

So, rather than allowing performance issues to annoy your customers, you are better off preventing those issues using Hypersistence Optimizer and enjoying spending your time on the things that you love!

Introduction

In this post, I’ll show you why you should not rely on the AUTO GenerationType strategy if you’re using MySQL and Hibernate.

As I already mentioned, you should never use the TABLE identifier generator since it does not scale properly.

Read More

The JPA EntityManager createNativeQuery is a Magic Wand

Are you struggling with performance issues in your Spring, Jakarta EE, or Java EE application?

Imagine having a tool that could automatically detect performance issues in your JPA and Hibernate data access layer long before pushing a problematic change into production!

With the widespread adoption of AI agents generating code in a heartbeat, having such a tool that can watch your back and prevent performance issues during development, long before they affect production systems, can save your company a lot of money and make you a hero!

Hypersistence Optimizer is that tool, and it works with Spring Boot, Spring Framework, Jakarta EE, Java EE, Quarkus, Micronaut, or Play Framework.

So, rather than allowing performance issues to annoy your customers, you are better off preventing those issues using Hypersistence Optimizer and enjoying spending your time on the things that you love!

Introduction

I found this very interesting question on the Hibernate forum, and, in this post, I want to demonstrate to you why native SQL queries are awesome.

Read More

How to replace the TABLE identifier generator with either SEQUENCE or IDENTITY in a portable way

Are you struggling with performance issues in your Spring, Jakarta EE, or Java EE application?

Imagine having a tool that could automatically detect performance issues in your JPA and Hibernate data access layer long before pushing a problematic change into production!

With the widespread adoption of AI agents generating code in a heartbeat, having such a tool that can watch your back and prevent performance issues during development, long before they affect production systems, can save your company a lot of money and make you a hero!

Hypersistence Optimizer is that tool, and it works with Spring Boot, Spring Framework, Jakarta EE, Java EE, Quarkus, Micronaut, or Play Framework.

So, rather than allowing performance issues to annoy your customers, you are better off preventing those issues using Hypersistence Optimizer and enjoying spending your time on the things that you love!

Introduction

As previously explained, the TABLE identifier generator does not scale, so you should avoid id. However, some enterprise applications might need to run on both MySQL (which does not support database sequences), as well as Oracle, PostgreSQL, and SQL Server 2012.

This is article is going to explain how easily you can achieve this goal using the JPA mapping overriding.

Read More

Book Review – SQL Antipatterns

Are you struggling with performance issues in your Spring, Jakarta EE, or Java EE application?

Imagine having a tool that could automatically detect performance issues in your JPA and Hibernate data access layer long before pushing a problematic change into production!

With the widespread adoption of AI agents generating code in a heartbeat, having such a tool that can watch your back and prevent performance issues during development, long before they affect production systems, can save your company a lot of money and make you a hero!

Hypersistence Optimizer is that tool, and it works with Spring Boot, Spring Framework, Jakarta EE, Java EE, Quarkus, Micronaut, or Play Framework.

So, rather than allowing performance issues to annoy your customers, you are better off preventing those issues using Hypersistence Optimizer and enjoying spending your time on the things that you love!

Introduction

I’ve just finished the wonderful SQL Antipatterns book by Bill Karwin. The book is a must-have reference for any developer that has to interact with a relational database system.

This post is a review of what this book is all about and why you should be interested in reading it.

Read More

Why you should never use the TABLE identifier generator with JPA and Hibernate

Are you struggling with performance issues in your Spring, Jakarta EE, or Java EE application?

Imagine having a tool that could automatically detect performance issues in your JPA and Hibernate data access layer long before pushing a problematic change into production!

With the widespread adoption of AI agents generating code in a heartbeat, having such a tool that can watch your back and prevent performance issues during development, long before they affect production systems, can save your company a lot of money and make you a hero!

Hypersistence Optimizer is that tool, and it works with Spring Boot, Spring Framework, Jakarta EE, Java EE, Quarkus, Micronaut, or Play Framework.

So, rather than allowing performance issues to annoy your customers, you are better off preventing those issues using Hypersistence Optimizer and enjoying spending your time on the things that you love!

Introduction

From a data access perspective, JPA supports two major types of identifiers:

  • assigned
  • generated

The assigned identifiers must be manually set on every given entity prior to being persisted. For this reason, assigned identifiers are suitable for natural keys.

For synthetic Primary Keys, we need to use a generated entity identifier, which is supported by JPA through the use of the @GeneratedValue annotation.

There are four types of generated identifier strategies which are defined by the GenerationType enumeration:

  • AUTO
  • IDENTITY
  • SEQUENCE
  • TABLE

The AUTO identifier generator strategy chooses one of the other three strategies (IDENTITY, SEQUENCE or TABLE) based on the underlying relational database capabilities.

While IDENTITY maps to an auto-incremented column (e.g. IDENTITY in SQL Server or AUTO_INCREMENT in MySQL) and SEQUENCE is used for delegating the identifier generation to a database sequence, the TABLE generator has no direct implementation in relational databases.

This post is going to analyze why the TABLE generator is a poor choice for every enterprise application that cares for performance and scalability.

Read More