The latest from the MySQL community

In this tenth post of our series, we decode the ROTATE_EVENT — the event that closes a binary log file and tells every reader, replica or local, where to look next.

Introduction

The ROTATE_EVENT (event type 4, 0x04) is the bookmark MySQL leaves at the end of a binary log file. It carries two pieces of information:

• The name of the binary log file to read next.
• The starting position within that next file (always 4, the byte right after the 4-byte magic number from Part 2).

Together those two fields are enough for any reader — a replica's I/O thread, a mysqlbinlog invocation, a CDC tool — to seamlessly continue from one file into the next. …

May 2026 · 5 min read. Alkin Tezuysal

Cross blog from Oracle https://blogs.oracle.com/mysql/mysql-9-7-is-out-and-the-community-wins

MySQL 9.7 came out on April 21 and I’ve been going through the release notes so you don’t have to. The short version: Oracle has made several previously Enterprise-only features available in the Community Edition; the Hypergraph Optimizer is now free for everyone; and if you’re still on MySQL 8.0, it has reached End-of-Life. Like right now. We’ll get to that.

Let’s go through what matters most.

First: MySQL 8.0 has reached End-of-Life

MySQL 8.0.46 shipped alongside 9.7, and it is the last 8.0 release. As of April 2026, 8.0 is officially End-of-Life. No more security patches. No …

Alkin Tezuysal Director of Services at Altinity Inc. MySQL 9.7 came out on April 21 and I’ve been going through the release notes so you don’t have to. The short version: Oracle has made several previously Enterprise-only features available in the Community Edition, the Hypergraph Optimizer is now free for everyone, and if you’re still on MySQL 8.0, it […]

Many applications start with a simple database setup: create one MySQL user, give it access to the application schema, put the credentials in the app config, and move on. That may work at first, but it is not a good long-term security model. A better approach is to use separate MySQL users for separate application […]

In this blog, I am going to share a real-world debugging case study where a routine Percona XtraDB Cluster node restart led to an unexpected failure. I will walk through what we observed, what we checked, and how we ultimately identified the root cause.

Let’s see how the maintenance goes. It was supposed to be a simple restart. The kind you’ve done a hundred times. You SSH in, run the maintenance, bring the node back up, and go grab a coffee. Except this time, the coffee went cold on the desk… because MySQL refused to start.

The Problem

The error log of Percona XtraDB Cluster (8.0) had the following information:

2025-11-05T05:26:10.982984Z 0 [ERROR] [MY-000059]   [Server] SSL error: Unable to get certificate from '/var/lib/mysql/server-cert.pem'.
2025-11-05T05:26:10.983030Z 0 [Warning] [MY-013595] [Server] Failed to initialize TLS for channel: mysql_main. See below for the description of exact issue. …

Percona Monitoring and Management is a great open source database monitoring, observability, and management tool. Query analytics is one of the prominent features DBA uses actively to trace the incidents and query performance identification.

We all know and love the Query Analytics (QAN) dashboard… It’s the first place we look when an incident alert fires or when a developer asks, “Why is the app slow?” or “What was going on during the midnight production outage?”

But sometimes, the standard dashboards just don’t tell the whole story or maybe are not clear enough. QAN is great, but shouldn’t we have more? If you have PMM running, you already have a Ferrari engine under the hood: ClickHouse. Most of us just drive it in first gear using the default UI.

In this post, we are going to take the training wheels off. We will bypass the standard QAN interface and talk directly to the ClickHouse backend to …

Introduction

Many MySQL configurations inherit redo log sizing from defaults, aging blog posts, or configuration folklore.

innodb_redo_log_capacity gets set once… and then quietly fades into the background.

But redo log capacity directly shapes how efficiently MySQL absorbs writes, manages checkpoint pressure, and handles burst-heavy workloads.

Set it too low, and aggressive flushing can throttle throughput.
Set it too high, and crash recovery can become painfully long.

Redo logs are more than crash insurance.

They are part of your write-performance architecture.

Redo logs are the shock absorbers of write-heavy MySQL. Too small, and performance jolts. Too large, and recovery drags.

Why Redo Logs Matter

InnoDB redo logs are often described as crash recovery journals, but that description undersells their real operational value.

Redo …

Recently, we received an alert for one of our Managed Services customers indicating that the auto_increment value for the table was 80% of its maximum capacity. The column was INT UNSIGNED, which has a limit of 4,294,967,295.

At 80%, we have enough time to change it to BIGINT.…. Right? Let’s see.

So we used pt-online-schema-change to perform the alter.

It started running at a good pace but slowed over time.

Why?

Well, let’s look at the definition of the table:

mysql> show create table myschema.mytableG
*************************** 1. row ***************************
       Table: mytable
Create Table: CREATE TABLE `mytable` (
  `id` int unsigned NOT NULL AUTO_INCREMENT,
  `long_column` …

Once you move from self-managed MySQL to a MySQL DB System with HeatWave on OCI, the tuning story changes in an important way. On a self-managed server, you worry about two layers: MySQL and the operating system. On OCI MySQL DB Systems with HeatWave, Oracle runs your MySQL instance as a fully-managed service and explicitly […]

MySQL 9.7 introduces a long-requested improvement: Child table triggers are executed during SQL-layer foreign key cascades. Historically, cascades executed inside InnoDB did not invoke child table triggers, which created gaps in auditing, derived data maintenance, and observability. When a parent row change triggered cascading changes in child tables, those child table triggers were not executed. This […]