Every year new cohorts of programmers, DBAs, managers, and more learn MySQL. After MySQL and HeatWave Summit 2025 a few weeks ago, I realized what job needs to be done for these people and how I could help them make progress: revamping this website to focus on “the path”.

MySQL provides the MySQL Community Edition, the Open-Source version. In addition, there is the Enterprise Edition for our Commercial customers and MySQL HeatWave, our managed database service (DBaaS) on the cloud (OCI, AWS, etc.). But do you know developers can freely use MySQL Enterprise for non-commercial use? The full range of MySQL Enterprise Edition features […]

Sometimes, MySQL throws an error like this:

Host ‘…’ is blocked because of many connection errors

Unblock with ‘mysqladmin flush-hosts’

This typically means that MySQL has blocked a host after too many connection errors. The usual fix is to run:

mysqladmin flush-hosts

or

mysql> FLUSH HOSTS; /* deprecated since 8.0.23; invalid in 8.4 */
mysql> TRUNCATE TABLE performance_schema.host_cache; /* recommended since 5.6.5 */

A host is blocked, because of many connection errors, specifically more connection errors than max_connect_errors.

So

• what counts as a connection error?
• what is counted per what?
• and how is the error count cleared?

…

Introduction In this article, I’m going to show you how to optimize the queries executed by a Spring application running on MySQL using Releem. For a short introduction about Releem, check out this previous article, in which I explained how to set up Releem to collect metrics from your MySQL database. Spring Petclinic application The application under test is going to be the well-known Spring Petclinic that we are going to run using the MySQL profile: After starting the application, we are going to run the petclinic_test_plan.jmx JMeter test plan that is... Read More

The post MySQL Query Optimization with Releem appeared first on Vlad Mihalcea.

Modern applications need to be highly available and easy to scale. A three-node MySQL InnoDB Cluster—built on MySQL Group Replication and connected through MySQL Router—provides a reliable way to support critical workloads. To set up this architecture, you start by deploying three MySQL server instances. In this example, the nodes are assigned the following hostname-to-IP […]

The latest update to MySQL Enterprise Edition, version 9.3, introduces a significant enhancement focused on improving primary selection on failover. This update includes an improvement to Group Replication primary failover, providing users with a better selection method of a new primary based on the member's most current data. This enhancement results in a seamless experience during failover, maintaining high availability and data integrity.

This post provides information on how to choose the appropriate shape when migrating your MySQL workload from on-premise to HeatWave (MySQL) in Oracle Cloud Infrastructure. The post also provides some additional information for a successful migration.

Before the MySQL & HeatWave Summit, we released MySQL 9.3, the latest Innovation Release. The event was terrific, and I had the chance to meet some of the MySQL contributors. As usual, we released bug fixes for 8.0 and 8.4 LTS, but I focus on the newest release in this post.

Before the MySQL & HeatWave Summit, we released MySQL 9.3, the latest Innovation Release. The event was terrific, and I had the chance to meet some of the MySQL contributors. As usual, we released bug fixes for 8.0 and 8.4 LTS, but I focus on the newest release in this post.We included patches and code […]

This blog post describes the latest performance improvement in semi-join / anti-join queries.