In MySQL 5.6, one of the most well received changes was improving the default configuration to be safer, and easier to use.
We are seeking community feedback for improvements that can be made to the default configuration in MySQL 5.7. Please leave a comment, or get in touch with me via email.
For elimination of confusion, please state both the setting you would like changed, and the new desired value.
Thanks!
It struck me today; there is an easy way to describe MySQL's Binary Log group commit improvements from MySQL 5.0-5.7 by using the example of a single ferry trying to ship passengers from point A to point B:
MySQL 5.0 Behaviour
In MySQL 5.0, the ferry will pick up the next passenger in line from point A, and transfer them to point B. The trip between A and B takes about 10 minutes return trip, so it's possible that several new passengers will arrive while the ferry is in transit. That doesn't matter; when the ferry arrives back at point A, it will only pick up the very next passenger in line.
MySQL 5.6 Behaviour
In MySQL 5.6, the ferry will pick up all passengers from the line at point A, and then transfer them to point B. Each time it returns to point A to pick up new passengers, it will collect everyone who is …
[Read more]Stop increasing max_connections every time there’s a 1040: Too Many Connections error. Every additional connection is another share to further divide the available memory.
Instead, while it would be best to manage the workload, it is also reasonable to properly utilize the available hardware with good server configuration.
There are three relevant server configuration options for managing connection counts as they relate to satisfying web requests.
Correctly configuring these three variables, and controlling your workload of course, can prevent 1040 Too many connections errors, assuming, …
[Read more]While doing some testing (that I published later here) on the still-in-development MySQL 5.7 I wanted to do some analysis on the configuration to see if the changes in performance were due to the code changes or just to the new MySQL defaults (something that is very common in the migration from 5.5 to 5.6 due to the default transaction log size and other InnoDB parameters). This is a quick post aiming to identify the global variables changed between these two versions.
You could tell me that you could just read the release notes, but my experience (and this is not an exception, as you will see) …
[Read more]I've been experimenting with MySQL Fabric - the official tool in development to provide HA and sharding. Part of this experimentation has meant that I have been running 7 copies of the MySQL Server on my laptop at once, which can consume a lot of memory
So today I wanted to write about how to configure MySQL to use less memory, which may also be beneficial in situations where peak performance is not important. For example: a developer VM environment.
Previous configuration guides
Before I get started, let me point to some of my previous configuration guides:
You may think that you already know what's the opposite of
"DISABLED", but with MySQL Event Scheduler you'll be wrong.
In fact MySQL Event Scheduler may have three different
states[1][2]:
DISABLED - The Event Scheduler thread does not run [1]. In addition, the Event Scheduler state cannot be changed at runtime. OFF (default) - The Event Scheduler thread does not run [1]. When the Event Scheduler is OFF it can be started by setting the value of event_scheduler to ON. ON - The Event Scheduler is started; the event scheduler thread runs and executes all scheduled events.
So if you're going to find it in the DISABLED state and
instinctively set it to ENABLED you'll end up with a
non-starting MySQL daemon.
Be warned and stay safe out there!
[1]:
http://dev.mysql.com/doc/refman/5.5/en/events-configuration.html
[2]: When the Event Scheduler is not running does not appear …
October 16, 2013 By Severalnines
Galera uses a preallocated file with a specific size called gcache, used to store the writesets in circular buffer style. By default, its size is 128MB. In this post, we are going to explore how to leverage gcache to improve the operation of a Galera cluster.
Test Case
We have a four node Galera cluster, using the latest release 23.2.7(r157). We have a table called t1 that is replicated by Galera on all nodes. The cluster nodes have allocated the default 128MB gcache.size, and we’ll try to execute a large writeset to see how gcache responds.
mysql> SHOW VARIABLES LIKE …[Read more]
July 2, 2013 By Severalnines
Joomla! is estimated to be the second most used CMS on the internet after WordPress, with users like eBay, IKEA, Sony, McDonald’s and Pizza Hut. In this post, we will describe how to scale Joomla on multiple servers. This architecture not only allows the CMS to handle more users, by load-balancing traffic across multiple servers. It also brings high availability by providing fail-over between servers.
This post is similar to our previous posts on web application scalability and high availability:
Upgrading from MySQL 5.5 to MySQL 5.6 is a fairly straightforward process. However, the move to version 5.6 does bring with it some new varaibles with which to work.
One of the recent innovations (pioneered by Percona in Percona Server 5.5 if I recall correctly) is the ability to "dump" the innodb buffer pool***. This can be done any time MySQL is running and can be configured to be executed during MySQL shutdown. One reason to do this is to have a server "pre-warmed" when you perform a server restart. Why this is important is that during server operation the innodb buffer pool will fill up. Typically the server will operate much better when this buffer pool is full instead of being empty or paritally full because the return of data from the buffer pool is much faster than returning data from disk.
There are four important variables with each having a value of 'ON' or 'OFF'.
innodb_buffer_pool_dump_at_shutdown …
[Read more]June 11, 2013 By Severalnines
Over the years, WordPress has evolved from a simple blogging platform to a CMS. Over seven million sites use it today, including the likes of CNN, Forbes, The New York Times and eBay. So, how do you scale Wordpress on multiple servers for high performance?
This post is similar to our previous post on Drupal, Scaling Drupal on Multiple Servers with Galera Cluster for MySQL but we will focus on Wordpress, Percona XtraDB Cluster and GlusterFS using Debian Squeeze 64bit.
