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Displaying posts with tag: Percona Toolkit (reset)
Using Percona Toolkit to Alter Database Tables Online: A Controlled Approach

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 …

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Two Extremely Useful Tools (pt-upgrade and checkForServerUpgrade) for MySQL Upgrade Testing

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 …

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Finding Differences Between MySQL Servers

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: …

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Synchronize Tables on the Same Server with pt-table-sync

It is a common use case to synchronize data in two tables inside MySQL servers. This blog post describes one specific case: how to synchronize data between two different tables on the same MySQL server. This could be useful, for example, if you test DML query performance and do not want to affect production data. After few experiments, tables get out of sync and you may need to update the test one to continue working on improving your queries. There are other use cases when you may need to synchronize the content of the two different tables on the same server, and this blog will show you how to do it.

Table Content Synchronization

The industry-standard tool for table content synchronization – pt-table-sync – is designed to synchronize data between different MySQL servers and does not support bulk synchronization between two …

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Online DDL in Vitess

Vitess introduces a new way to run schema migrations: non-blocking, asynchronous, scheduled online DDL. With online DDL Vitess simplifies the schema migration process by taking ownership of the operational overhead, and providing the user a simple, familiar interface: the standard ALTER TABLE statement. Let’s first give some background and explain why schema migrations are such an issue in the databases world, and then dive into implementation details The relational model and the operational overhead # The relational model is one of the longest surviving models in the software world, introduced decades ago and widely used until today.

Dangerous Edge Case Warning for Percona Toolkit and pt-online-schema-change

Recently I was dealing with an unexpected issue raised by our Support customer, in which data became inconsistent after a schema change was applied.

After some investigation, it turned out that affected tables had a special word in the comments of some columns, which triggered an already known (and fixed) issue with the TableParser.pm library of Percona Toolkit.  The problem is that the customer was using an outdated Toolkit version, where pt-online-schema-change was using that buggy parser.

This bug applies only to Percona Toolkit versions up to 3.0.10, so if you have already 3.0.11 or newer installed, you can skip the rest of this post as these are no longer affected.

I am writing this post to warn every user of pt-online-schema-change who has not upgraded the toolkit, as …

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Percona Toolkit 3.1.0 Is Now Available

Percona announces the release of Percona Toolkit 3.1.0 on September 13, 2019.

Percona Toolkit is a collection of advanced open-source command-line tools, developed and used by the Percona technical staff, that are engineered to perform a variety of MySQL®, MongoDB®, PostgreSQL® and system tasks that are too difficult or complex to perform manually. With over 1,000,000 downloads, Percona Toolkit supports Percona Server for MySQL, MySQL, MariaDB, PostgreSQL, Percona Server for MongoDB, and MongoDB.

Percona Toolkit, like all Percona software, is free and open source. You can download packages  …

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Upcoming Webinar Wed 2/6: Percona Software News and Roadmap Update

Join Percona CEO Peter Zaitsev as he presents Percona Software News and Roadmap Update on Wednesday, February 6, 2019, at 11:00 AM PST (UTC-8) / 2:00 PM EST (UTC-5).

Register Now

Come and listen to Percona CEO Peter Zaitsev discuss what’s new in Percona open source software. Topics include Percona Server for MySQL and MongoDB, Percona XtraBackup, Percona Toolkit, Percona XtraDB Cluster and Percona Monitoring and Management.

During this …

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Percona Toolkit 3.0.13 Is Now Available

Percona announces the release of Percona Toolkit 3.0.13 for January 9, 2019.

Percona Toolkit is a collection of advanced open source command-line tools, developed and used by the Percona technical staff, that are engineered to perform a variety of MySQL®, MongoDB® and system tasks that are too difficult or complex to perform manually. With over 1,000,000 downloads, Percona Toolkit supports Percona Server for MySQL, MySQL®, MariaDB®, Percona Server for MongoDB and MongoDB.

Percona Toolkit, like all Percona software, is free and open source. You can download packages  …

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Caveats With pt-table-checksum Using Row-Based Replication, and Replication Filters

As per the documentation, pt-table-checksum is a tool to perform online replication consistency checks by executing checksum queries on the master, which produces different results on replicas that are inconsistent with the master.

The master and each slave insert checksums into the percona.checksums table, and these are later compared for differences. It’s fairly obvious that the checksums need to be determined independently on each node, and so these inserts must be replicated as STATEMENT and not ROW. Otherwise, the slaves would just insert the same checksum as the master and not calculate it independently.

The tool only requires

binlog_format=STATEMENT

  for its own session. It sets this itself on the master, but will error if this isn’t already set on each slave node. The …

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