The best way to use the Spring Transactional annotation

Introduction In this article, I’m going to show you the best way to use the Spring Transactional annotation. This is one of the best practices I applied when developing RevoGain, a web application that allows you to calculate the gains you realized while trading stocks, commodities, or crypto using Revolut.

Connection Monitoring with JPA and Hibernate

Introduction In this article, I’m going to show you how you can set up connection monitoring for your JPA and Hibernate application, no matter if you are using Spring or other application frameworks.

Read-write and read-only transaction routing with Spring

Introduction In this article, I’m going to explain how you can implement a read-write and read-only transaction routing mechanism using the Spring framework. This requirement is very useful since the Single-Primary Database Replication architecture not only provides fault-tolerance and better availability, but it allows us to scale read operations by adding more replica nodes.

PostgreSQL triggers and isolation levels

Introduction In this article, we are going to see how the PostgreSQL isolation levels guarantee read and write consistency when executing database triggers. While relational database systems provide strong data integrity guarantees, it’s very important to understand how the underlying transactional engine works in order to choose the right design for your data access layer.

How to log the database transaction id using MDC

Introduction In this article, I’m going to show you how you can log the database transaction id associated with a given SQL statement using the MDC (Mapped Diagnostic Context) feature offered by many logging frameworks. If you are writing data access code, you have to use logging. As I explained in this article, using a JDBC proxy tool like datasource-proxy or p6spy is the best approach to logging SQL statements. With datasource-proxy, you can easily build a JUnit extension to automatically detect N+1 query issues. For more details, check out the db-util… Read More

Spring read-only transaction Hibernate optimization

Introduction In this article, I’m going to explain how the Spring read-only transaction Hibernate optimization works. After taking a look at what the Spring framework does when enabling the readOnly attribute on the @Transactional annotation, I realized that only the Hibernate flush mode is set to FlushType.MANUAL without propagating the read-only flag further to the Hibernate Session. So, in the true spirit of open-source software developer, I decided it’s time to make a change.

A beginner’s guide to Phantom Read anomaly

Introduction Database transactions are defined by the four properties known as ACID. The Isolation Level (I in ACID) allows you to trade off data integrity for performance. The weaker the isolation level, the more anomalies can occur, and in this article, we are going to describe the Phantom Read phenomenon.

A beginner’s guide to Non-Repeatable Read anomaly

Introduction Database transactions are defined by the four properties known as ACID. The Isolation Level (I in ACID) allows you to trade off data integrity for performance. The weaker the isolation level, the more anomalies can occur, and in this article, we are going to describe the Non-Repeatable Read phenomenon.

A beginner’s guide to Dirty Read anomaly

Introduction Database transactions are defined by the four properties known as ACID. The Isolation Level (I in ACID) allows you to trade off data integrity for performance. The weaker the isolation level, the more anomalies can occur, and in this article, we are going to describe the Dirty Read phenomenon.

How to extract change data events from MySQL to Kafka using Debezium

Introduction As previously explained, CDC (Change Data Capture) is one of the best ways to interconnect an OLTP database system with other systems like Data Warehouse, Caches, Spark or Hadoop. Debezium is an open-source project developed by Red Hat which aims to simplify this process by allowing you to extract changes from various database systems (e.g. MySQL, PostgreSQL, MongoDB) and push them to Apache Kafka. In this article, we are going to see how you can extract events from MySQL binary logs using Debezium.