July 24, 2014

8 common (but deadly) MySQL operations mistakes and how to avoid them

January 22 I gave a presentation on “How to Avoid Common (but Deadly) MySQL Operations Mistakes” for Percona MySQL Webinars. If you missed it, you can still register to view the recording and my slides. Thanks to everyone who attended, and especially to folks who asked the great questions. I answered as many as we […]

Calvin Sun on MySQL at Twitter, Percona Live 2014 and Facebook

Twitter’s Calvin Sun (@Calvinsun2012) is looking forward to the fast-approaching Percona Live MySQL Conference and Expo this April 1-4 in Santa Clara, Calif. He’ll be speaking, yes, but he’s also looking forward to learning from his peers – particularly those at Facebook. Both companies, he explained, are in the rather unique positions of unprecedented rapid […]

10 MySQL settings to tune after installation

When we are hired for a MySQL performance audit, we are expected to review the MySQL configuration and to suggest improvements. Many people are surprised because in most cases, we only suggest to change a few settings even though hundreds of options are available. The goal of this post is to give you a list […]

Q&A: Geographical disaster recovery with Percona Replication Manager

My December 4 webinar, “Geographical disaster recovery with  Percona Replication Manager (PRM),”  gave rise to a few questions. The recording of the webinar and the slides are available here, and I’ve answered the questions I didn’t have time to address below. Q1: Hi, I was wondering if corosync will work in cloud environment. As far as […]

MySQL 5.6’s new replication features: Benefits, Limitations and Challenges

On Wednesday I’ll be leading a webinar exploring MySQL 5.6’s new replication features. And yes, as usual I’ll deliver news on the good, the bad and the ugly (that is to say the benefits, limitations and challenges). The webinar, appropriately titled, “New Replication Features in MySQL 5.6: Benefits, Limitations, and Challenges“, is scheduled for Oct. […]

Innotop: A real-time, advanced investigation tool for MySQL

GUI monitoring tools for MySQL are not always suitable for all our needs or situations. Most of them are designed to provide historical views into what happens to our database over time rather then real-time insight into current MySQL server status. Excellent free tools for this include Cacti, Zabbix, Ganglia, Nagios, etc. But each of […]

5 reasons why MySQL replication lag is flapping between 0 and XXXXX

Working day to day with Percona Remote DBA customers, we have been facing an issue from time to time when MySQL replication lag is flapping between 0 and XXXXX constantly – i.e. Seconds_Behind_Master is 0 for a few secs, then it’s like 6287 or 25341, again 0 and so on. I would like to note […]

Enabling crash-safe slaves with MySQL 5.6

Being able to configure slaves to be crash-safe is one of the major improvements of MySQL 5.6 with regards to replication. However we noticed confusion on how to enable this feature correctly, so let’s clarify how it should be done. In short 1. Stop MySQL on slave 2. Add relay_log_info_repository = TABLE and relay_log_recovery = […]

Another reason why SQL_SLAVE_SKIP_COUNTER is bad in MySQL

It is everywhere in the world of MySQL that if your replication is broken because an event caused a duplicate key or a row was not found and it cannot be updated or deleted, then you can use ‘ STOP SLAVE; SET GLOBAL SQL_SLAVE_SKIP_COUNTER=1; START SLAVE; ‘ and be done with it. In some cases this is fine and you can repair the […]

Crash-resistant replication: How to avoid MySQL replication errors

Percona Server’s “crash-resistant replication” feature is useful in versions 5.1 through 5.5. However, in Percona Server 5.6 it’s replaced with Oracle MySQL 5.6′s “crash safe replication” feature, which has it’s own implementation (you can read more about it here). A MySQL slave normally stores its position in files master.info and relay-log.info which are updated by […]