October 20, 2014

Database auditing alternatives for MySQL

Database auditing is the monitoring of selected actions of database users. It doesn’t protect the database in case privileges are set incorrectly, but it can help the administrator detect mistakes. Audits are needed for security. You can track data access and be alerted to suspicious activity. Audits are required for data integrity. They are the […]

Errant transactions: Major hurdle for GTID-based failover in MySQL 5.6

I have previously written about the new replication protocol that comes with GTIDs in MySQL 5.6. Because of this new replication protocol, you can inadvertently create errant transactions that may turn any failover to a nightmare. Let’s see the problems and the potential solutions. In short Errant transactions may cause all kinds of data corruption/replication […]

MySQL Audit Plugin now available in Percona Server 5.5 and 5.6

The new Percona Server 5.5.37-35.0 and Percona Server 5.6.17-65.0-56, announced yesterday (May 6), both include the open source version of the MySQL Audit Plugin. The MySQL Audit Plugin is used to log all queries or connections (“audit” MySQL usage). Until yesterday’s release, the MySQL Audit Plugin was only available in MySQL Enterprise. EDIT:  Just to be clear, this implementation […]

Row-based replication, MySQL 5.6 upgrades and temporal data types

Whither your rollback plan? MySQL 5.6 upgrades are in full swing these days and knowing how to safely upgrade from MySQL 5.5 to 5.6 is important. When upgrading a replication environment, it’s important that you can build a migration plan that safely allows for your upgrade with minimal risk — rollback is often a very […]

How to identify and cure MySQL replication slave lag

Here on the Percona MySQL Support team, we often see issues where a customer is complaining about replication delays – and many times the problem ends up being tied to MySQL replication slave lag. This of course is nothing new for MySQL users and we’ve had a few posts here on the MySQL Performance Blog […]

Looking to upgrade to MySQL 5.6? Check out my webinar on Jan 29!

We are nearing the one-year anniversary since MySQL 5.6 went GA – which is typically a good time even for the most conservative users to start thinking about upgrading. At this point there is a fair amount of practical use and experience; many bugs have also been fixed (1991 to be exact according to Morgan […]

MySQL server memory usage troubleshooting tips

There are many blog posts already written on topics related to “MySQL server memory usage,” but nevertheless there are some who still get confused when troubleshooting issues associated with memory usage for MySQL. As a Percona support engineer, I’m seeing many issues regularly related to heavy server loads – OR OOM killer got invoked and […]

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 […]

Handling long-running queries in MySQL with Percona XtraBackup

I recently had a case where replication lag on a slave was caused by a backup script. First reaction was to incriminate the additional pressure on the disks, but it turned out to be more subtle: Percona XtraBackup was not able to execute FLUSH TABLES WITH READ LOCK due to a long-running query, and the […]

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 […]