pt-online-schema-change is an amazing tool for assisting in table modifications in cases where ONLINE ALTER is not an option. But if you have foreign keys, this could be an interesting and important read for you. Tables with foreign keys are always complicated, and they have to be handled with care. The use case I am […]

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 […]

Table modifications are a routine task for database administrators. The blog post Using Percona Toolkit to Alter Database Tables Online: A Controlled Approach provides insights into the process of altering tables online in a controlled manner, ensuring uninterrupted access for application users and preventing application downtime. We will focus here on utilizing the powerful “pt-online-schema-change” […]

In Percona Managed Services, we manage Percona for MySQL, Community MySQL, and MariaDB. Sometimes, the replica server might have replication errors, and the replica might be out of sync with the primary. In this case, we can use Percona Toolkit’s pt-table-checksum and pt-table-sync to check the data drift between primary and replica servers and make […]

If you’re a DBA, one of your “easiest” tasks is to stop/start MySQL during a maintenance window, but even that could lead to unwanted scenarios if you modify some dynamic parameters at some point in your instance.

Here’s a brief story of how this could happen, to make it clearer:

You’re a DBA managing a few MySQL servers. The application using one of them starts having issues on a Friday night, right before it’s time to leave; after a quick check, you notice the app is requesting more connections, and the hotfix is to up max connections; you change them dynamically, the fire is off, and so are you. Let your future self worry about finding the root cause and fixing it properly the following Monday.

But life happens; Monday is here with new challenges, and you already forgot about the connections issue… A few months later, a restart for MySQL is required, and surprise, surprise, right after …

Sometimes crucial data sharing is avoided because of compliance rules, organizational policies, or numerous security concerns. The common use cases involve sharing pt-mysql-summary, pt-stalk, and other OS-related details to assist Support Engineers or any other third-party team troubleshoot database-related issues.

In this context, pt-secure-collect is a very important utility from Percona, which helps capture the required information securely and also provides aid in masking the existing information.

Pt-secure-collect helps in collecting, sanitizing, and encrypting data from various sources. By default, this utility collects the output with the help of pt-stalk, pt-summary, and pt-mysql-summary.

Let’s see how this tool …

Table modifications are a common task for database administrators. In this blog, I’ll explain how to alter tables online in a controlled manner that does not disrupt application users or cause application downtime.

One of the tools in Percona Toolkit is pt-online-schema-change, a utility that alters the structure of a table without interfering with the reads or writes. The tool creates an empty copy of the table to alter and modify as desired before copying the rows from the original table into the new one.

When the copying is finished, it removes the original table and replaces it with the new one. Any changes made to data in the original tables during the copy process will be reflected in the new table as the tool creates triggers on …

My last blog, Percona Utilities That Make Major MySQL Version Upgrades Easier, detailed the tools available from the Percona toolkit that assists us with major MySQL version upgrades. The pt-upgrade tool aids in testing application queries and generates reports on how each question performs on servers running various versions of MySQL.

MySQL Shell Upgrade Checker is a utility that helps in compatibility tests between MySQL 5.7 instances and MySQL 8.0 upgrades, which is part of the mysql-shell-utilities. The util.checkForServerUpgrade() function checks whether the MySQL 5.7 instance is ready for the MySQL 8.0 upgrade and generates a report with warnings, errors, and notices for preparing the current MySQL 5.7 setup for upgrading to MySQL 8.0.

We can run this Upgrade Checker Utility in the current MySQL 5.7 …

When one is responsible for promoting application development from Dev through the various environments such as QA, UAT, etc., through Production, it is often useful to ensure that configurations in test environments are comparable to the final production environment.  This is especially true with systems where a team of DBAs manage the servers.

Obviously, the difference in performance could be due to differences in hardware, storage, networking, software configuration, etc.  The question is how does one quickly and efficiently find the differences without having to run a lot of different commands and compare the output.  Fortunately, our Percona Toolkit has a couple of utilities that can make this much easier.  When you are tasked with supporting large numbers of servers, efficiency is paramount and this is where the toolkit can really help you!

You can find more information on the Percona Toolkit here: …