While doing benchmarks on 5.7 and 8.0, I came across a performance regression in MySQL 8.0 over 5.7 and opened a bug (Bug #111353 : 3x Performance Regression from 5.7 to 8.0 on ALTER TABLE FORCE).  There has been recent activity on this bug, showing an easy workaround.  This, even if it is known since 16 July 2024, has not been talked about much, so this deserves a blog post.

When performing backups, reducing the amount of time your server is locked can significantly improve performance and minimize disruptions. Percona XtraBackup 8.4 Pro introduces improvements in how DDL (Data Definition Language) locks (aka Backup Locks) are managed, allowing for reduced locking during backups. In this post, we’ll explore the impact of these enhancements. TL;DR (Summary) […]

TL;DR ALTER TABLE and OPTIMIZE TABLE on an InnoDB table, which rebuilds the table without blocking concurrent changes to it (i.e., executed using INPLACE algorithm) and concurrent DML or purge activity on the table can occasionally lead to two significant problems: ALTER/OPTIMIZE TABLE failing with an unnecessary duplicate key error (even though there are no […]

In the last weeks / months, I have been working on understanding / improving MySQL startup with many tables.  I already wrote four posts on the subject, they are listed below.  In this post, I use the system analysis of the previous post to revisit the light optimization on EBS volumes.  With this analysis, I am able to determine why the previous tests did not show

I have been looking into “dolphie” lately, and have to say, “thanks Charles!”. I actually first saw dolphie via Lefred’s MySQL Belgian Days and installed it just after looking into the slidedeck. But never got around to looking further… until now.

We can use so many different observability (o11y?) tools to get notifications, alerts, react, generate reports, etc. from so many different companies, using agents, proxies, repositories, and so on and so forth. And after exchanging experiences with dolphie’s author himself, Charles, the idea here is to go that little bit further in …

This post is a little long, please bear with me as after the intro, you can skip to the essential.In the last weeks / months, I have been working on understanding / improving MySQL startup with many tables.  I already wrote three posts on the subject, they are listed below.  In this post, I focus on describing the startup phase InnoDB Tablespace Duplicate Check (Duplicate Check for

In the last weeks / months, I have been working on understanding / improving MySQL startup with many tables.  I already wrote two posts on the subject, the links are below.  So far, I did not share what brought my attention to this, and it is the subject of this post.  Also, and because it is related, I come back to the optimization / contribution I already made on

In the last weeks / months, I have been working on understanding / improving MySQL startup with many tables.  I already wrote a post about my work (Faster MySQL Startup with Many Tables).  In that post, I link to a bug report (Bug #115988 : Too Much Disk Read on Startup, penalizing deployments with many tables).  In that bug report, I write, without much details, that the

In this blog post, we will explore how network partitions impact group replication and the way it detects and responds to failures. In case you haven’t checked out my previous blog post about group replication recovery strategies, please have a look at them for some insight. Topology: [crayon-67f66f57d3f7c920418928/] Scenario 1: One of the GR nodes […]

I have been scratching my head about MySQL startup for some time.  There is much to say about this, and many other posts will probably follow.  For now, it is enough to know that with many tables (millions) the startup of MySQL 8.0+ (including 8.0, 8.4 and 9.0) is suboptimal (to say the least).  With very little changes, I was able to speed it up, from 2:39 to 1:09 (1 minute and 9