Author: Danil Zburivsky

Curious Case with MySQL Replication

MySQL Replication is a powerful tool and it’s hard to find a production system not using it. On the other hand debugging replication issues can be very hard and time consuming. Especially if your replication setup is not straightforward and you are using filtering of some kind. Let’s look at an issue I had..

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Designing Index to Eliminate Sorting

Using algorithm described in “Relational Database Index Design and the Optimizers by Tapio Lahdenmaki and Mike Leach”, I quickly came up with two indexes and while first one looked fine, I was really confused by the second one for the elimination of the sort. Let me show an example, not copy one from the book, but rather show a test I did with MySQL.

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Managing Production Systems: Document, test, verify, try again.

A couple of days ago I was reading a paper Paxos Made Live – An Engineering Perspective written by Google engineers. It is an interesting reading about implementation of Paxos algorithm for building a fault-tolerant database. But one paragraph made me think I am reading something very familiar…

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What Happens when InnoDB Fails to Start

Today I’ve spent some time (more than this issue was worth, actually) on a client’s system trying to find out why table was not accessible and failed. The error message suggested something went very wrong with .frm file and I already started thinking about restoring the table from backup, when I noticed that accessing any InnoDB table was producing same error. A quick check of the error log showed that when MySQL server was restarted some time ago InnoDB failed to initialize due to a memory issue.

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Audit a MySQL Instance with MySQLTuner

Quite often we need to perform a so-called “MySQL instance audit”. This common DBA procedure should give you a general view of the MySQL environment. You may be interested in a basic understanding of what kind of operation MySQL performs, how much memory does it use, or how well does it look from the performance point of view. There is no easy out-of-the-box way to do such an audit on a MySQL server. Fortunately there are several tools to make this process easier. Among most popular are mysqlreport and MySQLTuner. In this post I’d like to give a brief overview of MySQLTuner.

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