Typically, we receive customer tickets regarding crashes or bugs, where we request a core dump to analyze and identify the root cause or understand the unexpected behavior. To read the core dumps, we also request the linked libraries used by the server’s MySQL. However, there’s a more efficient way to achieve our goal: by using […]

I have been working on MyDumper for over three years now, and I usually don’t use the tax-consistency-only feature during backups because it wasn’t an option I quite understood. So, when reviewing another issue, I stepped into a curious scenario, and I finally got it and decided to share with you what I learned and when it should […]

As we know, Orchestrator is a MySQL high availability and replication management tool that aids in managing farms of MySQL servers. In this blog post, we discuss how to make the Orchestrator (which manages MySQL) itself fault-tolerant and highly available. When considering HA for the Orchestrator one of the popular choices will be using the Raft consensus. […]

You know about MySQL; we know about MySQL. After all, it’s been the most popular database system for years now. And now that we have that out of the way, on to the more important stuff! Because MySQL is so popular, you might be considering migrating your database to MySQL Community Edition or MySQL Enterprise. […]

Large tables can pose challenges for many operations when working with a database. Occasionally, we may need to modify the table definition. Since RDS replication does not use asynchronous for its replication, the typical switchover procedure is not feasible. However, the Blue/Green feature of RDS utilizes asynchronous replication, which allows us to update the table […]

What index will be used when you count all rows in a table? Well, the MySQL documentation provides a straightforward answer to this, quoting: InnoDB processes SELECT COUNT(*) statements by traversing the smallest available secondary index unless an index or optimizer hint directs the optimizer to use a different index. If a secondary index is […]

Here is part two of my MySQL with Diagrams series (Here’s part one – MySQL with Diagrams Part One: Replication Architecture). We are going to explore how MySQL handles thread termination using the KILL command, as visualized in the provided diagram, and provide sample demonstrations to help you better understand. Many people think they know […]

At Percona, we’ve always prioritized performance, and recent trends in MySQL’s development have been a point of concern for us. In particular, the performance deterioration in the MySQL 8.4.x and 9.y versions caught our attention, as highlighted in Marco Tusa’s insightful blog post, Sakila, Where Are You Going? We’re pleased to report that the latest […]

This blog post explains the cause of “ERROR 1412 (HY000): Table definition has changed, please retry transaction” with the specific Isolation level settings. Background As per the MySQL documentation, this error should occur for “operations that make a temporary copy of the original table and delete the original table when the temporary copy is built.” […]

In this series, “MySQL with Diagrams,” I’ll use diagrams to explain internals, architectures, and structures as detailed as possible. In basic terms, here’s how replication works: the transactions are written into a binary log on the source side, carried into the replica, and applied. The replica’s connection metadata repository contains information that the replication receiver […]