August 2, 2014

MySQL MyISAM Active Active Clustering – looking for trouble ?

Reading last few days worth of planet MySQL and commenting on some entries as you can see. The post by Oli catches my attention. There is also PDF with more details available Oli is saying you can use MySQL with Active Active Clustering and MyISAM tables if you follow certain rules like enabling external locking, […]

16000 active connections – Percona Server continues to work when others die

We just published results with improvements in Thread Pool in Percona Server: Percona Server: Thread Pool Improvements for Transactional Workloads Percona Server: Improve Scalability with Thread Pool What I am happy to see is that Percona Server is able to handle a tremendous amount of user connections. From our charts you can see it can […]

The top 5 proactive measures to minimize MySQL downtime

I’m happy to announce that the recording for my recent webinar “5 Proactive Measures to Minimize MySQL Downtime” is now available, along with the slides. They can both be found here. My webinar focused on the top 5 operational measures that prevent or reduce downtime — along with the related business impact in a significant […]

MySQL Webinar: 5 proactive measures to help minimize MySQL downtime, July 17

Failure is an unavoidable part of IT life, but it does not always have to imply MySQL service downtime. In the years I have been working at Percona, I have been involved in many customer emergency cases, and I have seen a good number of problems that could have been avoided or alleviated if relatively […]

Actively monitoring replication connectivity with MySQL’s heartbeat

Until MySQL 5.5 the only variable used to identify a network connectivity problem between Master and Slave was slave-net-timeout. This variable specifies the number of seconds to wait for more Binary Logs events from the master before abort the connection and establish it again. With a default value of 3600 this has been a historically […]

ACTIVE with Locks – Now thats a problem !

One of item I always look at SHOW ENGINE INNODB STATUS to see if there are any transactions spending very long time in ACTIVE state. In the perfect world if you’re running online system you should not see transactions spending more than couple of seconds in ACTIVE state. Especially ACTIVE transactions which do not currently […]

Active Cache for MySQL

One of the problems I have with Memcache is this cache is passive, this means it only stores cached data. This means application using Memcache has to has to special logic to handle misses from the cache, being careful updating the cache – you may have multiple data modifications happening at the same time. Finally […]

Queries Active vs Transactions Active

What is wrong here (the part of SHOW INNODB STATUS): ————– ROW OPERATIONS ————– 8 queries inside InnoDB, 9 queries in queue 100 read views open inside InnoDB It is relationship between queries active – queries inside innodb+queries in the queue totalling 17 with “read views open inside InnoDB” which is a fancy way of […]

Prevent MySQL downtime: Set max_user_connections

One of the common causes of downtime with MySQL is running out of connections. Have you ever seen this error? “ERROR 1040 (00000): Too many connections.” If you’re working with MySQL long enough you surely have. This is quite a nasty error as it might cause complete downtime… transient errors with successful transactions mixed with […]

Why TokuDB hates Transparent HugePages

If you try to install the TokuDB storage engine on a modern Linux distribution it might fail with following error message: 2014-07-17 19:02:55 13865 [ERROR] TokuDB will not run with transparent huge pages enabled. 2014-07-17 19:02:55 13865 [ERROR] Please disable them to continue. 2014-07-17 19:02:55 13865 [ERROR] (echo never > /sys/kernel/mm/transparent_hugepage/enabled) You might be curious […]