Archive for November, 2009

Is your database schema in sync?

Wednesday, November 25th, 2009

If you have more then a single MySQL database for your production environment, e.g. a development and test environment, or a MySQL replication topology, ensuring your schema’s are in sync can be task that requires some time if not managed correctly.

There is a tool I do use for MySQL environments called Schema Sync – a MySQL Schema Versioning and Migration Utility. There are many reasons why schema’s get out of sync. Developers may not ensure their changes are reflected in any software to be deployed, and when not tested you could end up with broken functionality. A DBA might try some different index strategies on a slave, but not the master, and never implement or revert.

While some people want the quick and hidden just sync version akin to Rails, I really like this product as it produces proper patch and revert SQL scripts. As a DBA I really want to know what’s going to be applied to my schema, I want to be able to review it before it’s just magically applied. The revert process is also ideal, in time critical situations when you may need to rollback a change, either it’s taking to long to deploy.

This is definitely a tool to use over time, especially if you have multiple developers, DBA’s and more then one MySQL environment that should be the same.

Monitoring MySQL with MONyog

Wednesday, November 25th, 2009

It just works. In absence of any MySQL monitoring for your site, I have found no solution that gets you operational as quickly and easily. MONyog can be deployed in 60 seconds, and configured in another 60 seconds. Within 5 minutes you can have visual monitoring of your MySQL environment.

MONyog is an agentless process, which is an advantage for easy install, but does not provide for monitoring redundancy in the capture of information due to agentless nature. It’s a static standalone executable which is great if you need something to work out of the box. You can easily configure multiple servers in a replication topology, or different servers in your environment. You get the ability to monitor all the usual information, with a dashboard and detailed graphs. While MONyog does provide customizations of rules for the graphs and presentation order, that’s about it. You can’t at this time for example change the colors, what’s on graphs except for what MONyog monitors or the security of certain options in the GUI to different users, however I hope they offer these suggestions in future releases.

MONyog includes some nice features that are overlooked in other products. You have the ability to monitor the MySQL error log (if configured appropriately) which is a common complaint of end users. You can also see the process list, and when configured you can also perform query gathering and analysis.

MONyog is a well priced commercial product with a free trial download without registration requirements which gives no barrier to access and evaluate. As a solution and ease of deployment, there is no excuse not to evaluate this product. If you have no monitoring, you can now quickly and easily. I find a number of clients that simply have no monitoring. There really is no excuse as it’s critical information you need to have and record for a successful business.

You can get it from www.webyog.com.

MySQL Permissions – Restarting MySQL

Thursday, November 19th, 2009

I am working with a client that is using managed hosting on dedicated servers. This has presented new challenges in obtaining the right permissions to undertake MySQL tasks but not have either ‘root’ or ‘mysql’ access and not have to involve a third party everytime.

Adding the following to the /etc/sudoers file enabled the ability to restart MySQL.

User_Alias	DBA = rbradfor, user2, etc
Host_Alias 	DB_SERVERS = server1.example.com, server2.example.com, etc
Cmnd_Alias	MYSQL = /etc/init.d/mysqld, /usr/sbin/tcpdump

DBA DB_SERVERS = MYSQL

As you can see I also got tcpdump, which I find valuable to monitor via mk-query-digest.

Next, permissions for log files.