September 16, 2014

Why is the ibdata1 file continuously growing in MySQL?

We receive this question about the ibdata1 file in MySQL very often in Percona Support. The panic starts when the monitoring server sends an alert about the storage of the MySQL server – saying that the disk is about to get filled. After some research you realize that most of the disk space is used […]

MySQL optimizer: ANALYZE TABLE and Waiting for table flush

The MySQL optimizer makes the decision of what execution plan to use based on the information provided by the storage engines. That information is not accurate in some engines like InnoDB and they are based in statistics calculations therefore sometimes some tune is needed. In InnoDB these statistics are calculated automatically, check the following blog […]

Percona Toolkit Webinar followup Q&A

First, a thank you to everyone who attended the webinar Today, I appreciate your time and nice comments. As promised, here are answers to questions that couldn’t be answered during the talk:   Q: How do you install the tools? The manual has full details, but it’s important to know that the latest release for […]

How FLUSH TABLES WITH READ LOCK works with Innodb Tables

Many backup tools including Percona Xtrabackup, MyLVMBackup and others use FLUSH TABLES WITH READ LOCK to temporary make MySQL read only. In many cases the period for which server has to be made read only is very short, just few seconds, yet the impact of FLUSH TABLES WITH READ LOCK can be quite large because […]

Faster Point In Time Recovery with LVM2 Snaphots and Binary Logs

LVM snapshots is one powerful way of taking a consistent backup of your MySQL databases – but did you know that you can now restore directly from a snapshot (and binary logs for point in time recovery) in case of that ‘Oops’ moment? Let me show you quickly how. This howto assumes that you already […]

Identifying the load with the help of pt-query-digest and Percona Server

Overview Profiling, analyzing and then fixing queries is likely the most oft-repeated part of a job of a DBA and one that keeps evolving, as new features are added to the application new queries pop up that need to be analyzed and fixed. And there are not too many tools out there that can make […]

Avoiding auto-increment holes on InnoDB with INSERT IGNORE

Are you using InnoDB tables on MySQL version 5.1.22 or newer? If so, you probably have gaps in your auto-increment columns. A simple INSERT IGNORE query creates gaps for every ignored insert, but this is undocumented behaviour. This documentation bug is already submitted. Firstly, we will start with a simple question. Why do we have […]

Innodb undo segment size and transaction isolation

You might know if you have long running transactions you’re risking having a lot of “garbage” accumulated in undo segment size which can cause performance degradation as well as increased disk space usage. Long transactions can also be bad for other reasons such as taking row level locks which will prevent other transactions for execution, […]

Virident tachIOn: New player on Flash PCI-E cards market

(Note: The review was done as part of our consulting practice, but is totally independent and fully reflects our opinion) In my talk on MySQL Conference and Expo 2010 “An Overview of Flash Storage for Databases” I mentioned that most likely there are other players coming soon. I actually was not aware about any real […]