Verifying MySQL Replication Integrity with pt-table-checksum

Short Form


pt-table-checksum is a free tool which safely and efficiently verifies that data on MySQL replicas is identical to the master. Having inconsistent data on MySQL replicas is a well-known and rather common problem, yet many people who depend on MySQL replication never check for it. Moreover, inconsistent data can be an expensive problem, but the solution is free: pt-table-checksum.


If you use MySQL replication but do not verify that data on replicas is the same as the master, then this session is for you. In it, you will learn:

  • Why inconsistent data can be an expensive problem (and why you should check for it)
  • Why pt-table-checksum is the right tool for detecting inconsistent data
  • How to use pt-table-checksum (in brief)
  • Four things to avoid that make pt-table-checksum sad
  • What pt-table-checksum does under the hood

With this knowledge, you will be able to use pt-table-checksum immediately and confidently to verify that data on your replicas is consistent with the master.

Speaking experience

I presented this talk at the MySQL Conference & Expo 2012, and will present it again at the 2013 conference.


  • Daniel Nichter

    Test Noir


    Daniel Nichter is the founder and creator of Test Noir, the web service that simplifies multi-environment software testing by centralizing, organizing, and analyzing your test results. He’s also the lead MySQL tools developer Percona, the oldest and largest independent MySQL consulting company. Daniel has been programming and developing with Perl and MySQL for 10 years.


      • Title: Quick Cure for the Shame of Untested Software
      • Track: Cooking
      • Room: B301
      • Time: 4:455:30pm
      • Excerpt:

        As the founder of a company focused on software testing, I speak often to developers who admit in private: “Yes, testing is important… but we don’t test.” Reasons vary, but the basic problem is that testing is seen as too difficult and time-consuming with no apparent value for the effort. In this talk I hope to convince you that this problem is a false dilemma and show you how to get started testing software quickly and easily.

      • Speakers: Daniel Nichter
      • Title: Pro Bash Development; Way Beyond Shell Scripting
      • Track: Hacks
      • Room: B302/303
      • Time: 2:303:15pm
      • Excerpt:

        All Unix/Linux users know a little shell scripting, even if they’re unaware of it. Pipes, for example, are a part of the Bash/sh language. Bash/sh, i.e. shell scripting, is usually treated as just that: shell scripting. But if you’re crazy enough, you can develop full-blown profession, modular, and tested (yes, tested!) programs in Bash. It takes a little finesse, but I’ll show you how, and you just might think twice about using Bash—really using it—in the future.

      • Speakers: Daniel Nichter