The Percona Database Performance Blog

“MongoDB was slow on Thursday”: answering the app team with mongo-health

Monday, 9:00. The app team writes: “MongoDB was slow on Thursday afternoon. What happened?” No alert fired, nobody looked at the time, and...

When a Small Change Writes Too Much – How A Linux Kernel Improvement Can Strike You in PXC/Galera Workloads

We’ve recently been dealing with an interesting customer case where a PXC version upgrade from 5.7 to 8.0 seemed to trigger a completely unexpected pr...

JavaScript in MySQL: Extending SQL, Not Moving the Application

At Percona Live Europe 2026, Dmitry Lenev and I presented JavaScript in My Database? Over My Dead Query, the story of component_js_lang, the V8-based ...

Thread Pool in Percona Server and MySQL (Part 2)

Thread Pool in Percona Server and MySQL (Part 2) The previous Part 1 focused on explaining the idea of thread pool, configuration options and analysis...

Meet MySQL 26.7: A New Versioning Era Begins

Over the period, we have witnessed how MySQL versioning evolved from 8.0 to 9.7 LTS, and now it has entered a new era: a calendar-based model. Let’s f...

MongoDB 9.0: More 8.4 than 9.0?

MongoDB 9.0 is here. Strip away the marketing around AI, Atlas, and “the best version ever built”, and MongoDB 9.0 starts to look a lot like MongoDB 8...

PGO or not PGO this is the dilemma. Step 3

Step 3: Why my sysbench-trained build loses and how to do it right. Given the topic complexity and the length of this article I have split it in 3 thr...

PGO or not PGO this is the dilemma. Step 2

Step 2: How it works Given the topic complexity and the length of this article I have split it in 3 three different blog-post: What is PGO How PGO it ...

PGO or not PGO this is the dilemma. Step 1

Given the topic complexity and the length of this article I have split it in 3 three different blog-post: What is PGO How PGO it works Why my sysbench...

Your Galera cluster’s hardest problem was never the replication library

Ask anyone who runs a multi-node MySQL Galera Cluster in production about their worst night. Almost nobody says write-set replication was wrong. They ...