October 25, 2014

Be productive with the MySQL command line

Even if you are using a GUI tool to connect to your MySQL servers, one day or another, you will have to deal with the command line. So it is nice to know a few tips that can really make your work easier. Note: The commands below are only available for Unix/Linux. Using pager Most […]

Zero-Downtime Schema Changes In MySQL

The recording of yesterday’s webinar, as well as a PDF of my slide deck, is now available. You can watch the recording and get the slides here. I got a lot of questions, and did not have enough time to answer all of them, so let me try to answer some of the remaining questions […]

Percona Replication Manager, a solution for MySQL high availability with replication using Pacemaker

The content of this article is outdated, look here for more up to date information. Over the last year, the frustration of many of us at Percona regarding issues with MMM has grown to a level where we started looking at other ways of achieving higher availability using MySQL replication. One of the weakness of […]

Why MySQL’s binlog-do-db option is dangerous

I see a lot of people filtering replication with binlog-do-db, binlog-ignore-db, replicate-do-db, and replicate-ignore-db. Although there are uses for these, they are dangerous and in my opinion, they are overused. For many cases, there’s a safer alternative.

New SpecJAppServer results at MySQL and Sun.

As you likely have seen Sun has posted the new SpecJAppServer Results More information from Tom Daly can be found here These results are quite interesting for me as I worked on some of the previous SpecJAppServer Benchmarks several years ago while being employed by MySQL. These are great results, plus they can be relevant […]

Poor man’s query logging

Occasionally there is a need to see what queries reach MySQL. The database provides several ways to share that information with you. One is called general log activated with

(or

in MySQL 5.1+) start-up parameter. The log writes any query being executed by MySQL to a file with limited amount of additional information. […]

Filtered MySQL Replication

To get this straight – I’m not a big fan of filtered or partial MySQL Replication (as of version MySQL 5.0) – there is enough gotchas with replication itself and getting things right with filtering can get quite bumpy road. In some applications however it is very helpful so lets see what one should do […]

Managing Slave Lag with MySQL Replication

The question I often get is how far MySQL may fall behind and how to keep replication from lagging. The lag you will see will vary a lot from application to the application and from load to load. Plus what is the most important within same application the lag will likely have spikes – most […]

Enabling/Disabling query log without server restart in MySQL 5.0

General query logging can be very handy in MySQL on profuction server for various debugging needs. Unfortunately you can’t switch it on and off without restarting server until MySQL 5.0. What can you do in MySQL 5.0 and below ? Use Our Patch – With this patch you can get all queries logged as slow […]

MySQL 4 to MySQL 5 Upgrade performance regressions

This week I already had two serious performance regression cases when upgrading from MySQL 4.0 and 4.1 to MySQL 5.0. By serious I mean several times performance difference not just 5-10% you often see for simple queries due to generally fatter code. The problem in both cases was MySQL 5.0 broken group commit bug. First […]