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Sveta Smirnovapt-pmp is a profiler tool that creates and summarizes full stack traces of processes on Linux. It was inspired by http://poormansprofiler.org and helped Percona Support resolve many performance issues. In this blog post, I will present an improved pt-pmp that can collect stack traces with minimal impact on the production environment. TLDR; Starting from Percona Toolkit […]
Starting from Percona Toolkit 3.6.0, pt-online-schema-change supports the option –where, so you can not only alter your table definition live but copy only rows that satisfy certain criteria. It may happen that you may not need to copy all the data when changing table definition. For example, if the table is too big and you […]
Starting from Percona Toolkit 3.6.0, you can resume pt-online-schema-change if it was interrupted. This blog describes the prerequisites and usage of the new –resume option. To restart the job, you need to know where it failed. This is why the first option you must use is –history. It instructs pt-online-schema-change to store its progress in […]
Percona Toolkit 3.6.0 has been released on June 12, 2024. The most important updates in this version are: The possibility to resume pt-online-schema-change if it is interrupted. eu-stack support in pt-pmp that significantly improves this tool’s performance and decreases the load it causes on production servers. New tool pt-eustack-resolver Packages for Ubuntu 24.04 (Noble Numbat) […]
A couple of weeks ago, we announced the first GA release of the PMM Dump: a new support tool that dumps Percona Monitoring and Management (PMM) metrics and Query Analytics (QAN) data to transfer to the expert engineer for review and performance suggestions. That blog introduced a command-line interface. A week later, PMM 2.0.41.0 was […]
Percona Toolkit 3.5.6 was released on December 21, 2023. This blog post covers the main changes in this release. New tool: pt-galera-log-explainer We continue adding more instruments for the Support teams. pt-galera-log-explainer was written by my Percona Support colleague Yoann La Cancellera. pt-galera-log-explainer filters, aggregates, and summarizes multiple Galera library logs together. The purpose of […]
In this post, I will present a new Percona tool: PMM Dump. The PMM Dump performs a logical backup of the performance metrics collected by the Percona Monitoring and Management (PMM) Server and imports them into a different PMM Server instance. PMM Dump allows you to share monitoring data collected by your PMM server securely […]
This blog post discusses using the CLONE INSTANCE command with the safety option DATA DIRECTORY when you do not have enough disk space to store two datasets. In my previous blog post on the CLONE INSTANCE command, The MySQL Clone Plugin Is Not Your Backup, I mentioned that using the option DATA DIRECTORY helps to avoid situations where you need to […]
Percona Toolkit 3.5.5 was released on October 3, 2023. This blog post covers the main changes in this release. pt-online-schema-change improvements After nibble hook This was contributed by Marcelo HP Ferreira at https://github.com/percona/percona-toolkit/pull/645. The feature allows you to define a custom plugin that will be triggered after copying each nibble. Here are a few examples […]
This blog post discusses the limitations of the MySQL Clone plugin. The MySQL clone plugin significantly simplifies the process of replica provisioning. All you need to do is: Ensure that the source server has binary logs enabled Grant appropriate permissions Execute the CLONE INSTANCE command on the recipient This works extremely easily when you provision a […]
This blog was originally published in November 2021 and was updated in September 2023. MySQL server performance can sometimes be perplexing, and if you’ve ever wondered about the role of triggers in influencing your MySQL server’s memory allocation, this post is for you. MySQL triggers are a powerful tool for database administrators and developers, enabling […]
In this blog, I will cover important aspects which you need to test when benchmarking replication setup. MySQL has great tools that could be used to test its performance. They include: sysbench – https://github.com/akopytov/sysbench BMK-kit – http://dimitrik.free.fr/blog/posts/mysql-perf-bmk-kit.html mysqlslap – https://dev.mysql.com/doc/refman/8.0/en/mysqlslap.html LinkBench – https://github.com/facebookarchive/linkbench I will not describe how to use them here, as you can […]
In this blog, I explain how to recover from a replication failure caused by a corrupted relay log file. MySQL replica stores data received from its source binary log in the relay log file. This file could be corrupted due to various reasons, mostly hardware failures. If this happens, replication will stop working, and the […]
In this blog, I will demonstrate how to use Percona Monitoring and Management (PMM) to find out the reason why the MySQL server is stalling. I will use only one typical situation for the MySQL server stall in this example, but the same dashboards, graphs, and principles will help you in all other cases. Nobody […]
For my previous blog post on the topic, I received plenty of questions about why I did not cover the caching_sha2_password plugin. This plugin is the default since MySQL 8, and all user accounts which are created without the option IDENTIFIED WITH, will use this plugin. Locally everything works fine because the plugin is built-in to […]
The utf8mb4 character set is the new default as of MySQL 8.0, and this change neither affects existing data nor forces any upgrades. Migration to utf8mb4 has many advantages including: It can store more symbols, including emojis It has new collations for Asian languages It is faster than utf8mb3 Still, you may wonder how migration […]
When MySQL client connects to the server it uses one of the authentication plugins. On the server-side, plugins are located in the directory, specified by the option plugin-dir that defaults to BASEDIR/lib/plugin where BASEDIR is the base directory of your MySQL installation. This perfectly works whenever you install MySQL using package manager, or from the […]
In Percona Support we spend a few hours per week doing Labs: short collective projects, not directly related to the tickets. One of our last labs was about to get ready for the winter holiday season which means preparing the tree and decorating it. To do it we used our favorite tools: MySQL, and ASCII […]
First I want to thank everyone who attended my November 16, 2021 webinar “MySQL Performance for DevOps“. Recording and slides are available on the webinar page. Here are answers to the questions from participants which I was not able to provide during the webinar. Q: Hi! We have troubles with DELETE queries. We have to […]
First, I want to thank everyone who attended my November 9, 2021 webinar “Introduction to MySQL Query Tuning for Dev[Op]s“. Recording and slides are available on our webinars page. Here are answers to the questions from participants which I was not able to provide during the webinar due to a technical issue we experienced at […]