The latest from the MySQL community

When setting up a new database for an application, high availability (HA) is one of the main priorities. Let’s assume for this example that you chose to use a Percona XtraDB (PXC) cluster to host your database. But how does the application know which PXC node is healthy and can receive application traffic? Introducing a cluster of ProxySQLs can solve this problem, as ProxySQL will healthcheck the database nodes and route the application traffic to the healthy nodes. However, now the HA problem comes up again: how does the application know which ProxySQL host is healthy?

Putting “one more component” in front of your servers to make them highly available just shifts the problem up by one layer. From making the database HA, to making ProxySQL HA, to needing to make HAProxy HA and so on…

At some point, you may land on the common HA strategy, keepalived, but BGP ECMP is a powerful alternative worth considering.

What …

Twitter login with Node breaks every few years because the pieces move under it. I rebuilt this app on the current releases and fixed each place where the old code stops working, so you can follow it step by step and finish with a working sign-in. Live Demo Download Code Pick the right X auth […]

As we have discussed through the new MySQL Community Engagement initiative, we are sharing metrics that highlight how the community contributes to MySQL. These measures help us understand the growth of community participation, recognize the people helping improve the product, and identify where we can continue to strengthen the contributor experience. The MySQL community delivered […]

In this guide, we explain 150+ SQL commands in simple words, covering everything from basic queries to advanced functions for 2026. We cover almost every SQL command that exists in one single place, so you never have to go search for anything anywhere else. If you master these 150 commands, you will become an SQL […]

An engineer leaves your company. You disable their single sign-on account, and their access to the wiki, the cloud console, and the CI system goes with it. Typically, access to database resources doesn't follow such a simple plan. Database user and role maintenance too often happens within the database, oblivious to single sign-on. User accounts carry a password which has to be managed and rotated (and the password is probably already sprawled out across shell history and a shared password manager).

An easier way to manage this is to bring the identity-provider model to the database. This is what the VillageSQL Server vsql-oauth2 extension does. It adds an authentication method that accepts an OAuth2/OpenID Connect token (a JWT) from your identity provider in place of a password. Your identity provider decides who can log in, MySQL privileges decide what they can do …

SQL problems become manageable when you turn the prompt into decisions about rows, columns, grouping, and result order, and I ran the worked example below with Python 3.11.16 and SQLite 3.53.1 so you can inspect how each clause changes the result. Start with the requested result Before writing SQL, mark the rows the prompt should […]

Percona Server for MySQL now ships with a fully open source OpenID Connect (OIDC) authentication plugin, available starting with Percona Server for MySQL 8.4.11-11 and 9.7.2-2 (not yet released as of this writing). It allows a MySQL account to authenticate against any standards-compliant Identity Provider (IdP) instead of relying on a locally stored password, closing the gap with MySQL Enterprise Edition, which has offered OIDC authentication since MySQL 9.1 and, in several respects, going beyond it.

Oracle offers the same category of functionality, but its server-side plugin is part of the paid MySQL Enterprise Edition. Percona’s implementation is open source and adds three capabilities the Enterprise plugin does not provide: automatic signing-key synchronization from a JWKS endpoint, IdP group-to-role mapping, and proxy-user support. This article explains how the plugin works and why those differences …

These 100 SQL MCQs with answers cover the concepts that appear repeatedly in beginner assessments, from SELECT and filtering through joins, grouping, constraints, and set operations. Answer each question before opening its explanation, then use every miss to name the SQL concept you need to practise in a database. How to use these SQL MCQ […]

Java Database Connectivity (JDBC) gives a Java program a standard API for opening a MySQL connection, sending SQL, and reading rows. The work starts with a compatible MySQL driver, a complete JDBC URL, and an account that can reach only the database your program needs. I compiled the example below with Maven resolving MySQL Connector/J […]

Posted on MySQL Ninjas | August 2026

Every DBA has been there. An alert fires. You SSH into the box, run free -h, and see MySQL consuming far more RAM than you configured. You double-check innodb_buffer_pool_size. It's set correctly. So where is the memory going?

This is the story of debugging exactly that — on a Google Cloud c4d-standard-4 instance with 14.7 GB RAM, MySQL configured with a 7168 MB buffer pool, and mysqld RSS sitting at 10.4 GB. That's a 3.2 GB gap nobody could explain.

The Setup

We run a large …