Introduction

Welcome to a new issue of the High-Performance Java Persistence Newsletter in which we share articles, videos, workshops, and StackOverflow answers that are very relevant to any developer who interacts with a database system using Java.

Articles

The pick of this edition is this article about using the MySQL Performance Schema for analyzing database transactions.

I’ve wanted to try Testcontainers for a very long time, so I finally had the time to use it to make Hibernate Types integration tests easier to run. For more details about Testcontainers, check out this article.

Using Spring Boot or Spring Framework has become the norm when developing Java-based web and enterprise applications. For this reason, it’s very important to know which are the best ways to fetch DTO projections, and for this reason, I wrote this article to help you with this task.

Another thing I’ve had to do for the Hibernate Types project is to use multiple Java versions for the main and test Maven folders. For more details about when you might need this and what solutions you have, then check out this article.

A lesser-known feature that was poorly documented is the rewriteBatchedStatements setting that you can enable to speed up MySQL INSERT statements.

Videos

I uploaded a new video on YouTube about SQL EXISTS and NOT EXISTS.

This video is part of my High-Performance SQL video course, so if you like this episode, you are going to love the video course.

Best Tweets

Here are the best tweets I posted since the last newsletter:

Devs who say Java is verbose have probably never built a Spring Boot application.

Spring Boot is one of the least verbose ways to build a fully-functional web app or service.

— Vlad Mihalcea (@vlad_mihalcea) August 14, 2022

SQL brings a lot to the table.

— Vlad Mihalcea (@vlad_mihalcea) August 7, 2022

The best way to learn about data structures and algorithms is by studying database systems.

- how B+Tree is built and scanned
- how index keys affect page fill factor or balancing
- nested loops vs hash join vs merge join
- hash vs stream aggregate

This is applied maths!

— Vlad Mihalcea (@vlad_mihalcea) August 10, 2022

A beginner’s guide to database multitenancy
https://t.co/JbshsqYXC0 pic.twitter.com/bg006fNamR

— Vlad Mihalcea (@vlad_mihalcea) August 13, 2022

20 years ago today I quit smoking. It was not easy, considering the numerous failed attempts.

Like many things in life, it's all about Persistence!

— Vlad Mihalcea (@vlad_mihalcea) August 23, 2022

Project Releases

I managed to release the 2.18 version of the Hibernate Types project, which provides two awesome features

• support for Testcontainers so that you can easily run the project test cases
• a Java Money CurrencyUnit type

PostgreSQL 14.5 has been released, offering various fixes and improvements for the PostgreSQL 14 branch.

Hibernate ORM has released several new versions for both the 5.6 and 6.1 branches:

• 5.6.11
• 6.1.2

If you’re using the amazing Hypersistence Optimizer, then you might want to upgrade to version 2.6.1, which fixes one issue related to Envers entities.

And, if you are not using Hypersistence Optimizer, you should know that you are missing out on a lot of performance optimization tips that could have been supplied to you automatically.

Get in touch with my latest articles!

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StackOverflow Answers

The following StackOverflow answers have been trending since the last newsletter episode:

• JPA – Batch/Bulk Update – What is the better approach?
• How to fix “Access to DialectResolutionInfo cannot be null” when ‘hibernate.dialect’ is not set
• How can I use FlexyPool with HikariCPFactory?
• PESSIMISTIC_WRITE locking is not working with Spring JPA Repository and Oracle 12c
• JPA orm.xml support for database index