As I prepare to convert some MySQL tables with FULLTEXT indexes from MyISAM to InnoDB I want to verify that running a standard production query set against the tables will return the same results with InnoDB that it did with MyISAM. Since I read Matt Lord's blog post about the document relevancy rankings used for InnoDB full-text searches I knew to expect some differences when sorting by relevancy, so I want to focus on getting the same set of rows back, mostly ignoring the order in which the rows are returned.

Percona toolkit has a tool called pt-upgrade that works well for this purpose. I used 2 test servers with a copy of my production database. On one of the servers I left the tables in MyISAM, and on the other I converted the tables to InnoDB. I …

While there are many graphing tools out there and we’ve used Munin for a while now.

The MySQL plugin for Munin had fallen out of date and the show engine innodb status output changed in 5.5 making some bits of the plugin simply not work any more. Also the show global status has some extra variables so there was a need to create new graphs.

All of these are now in the 2.1.8+ development releases of Munin.

Here are samples of the new/updated graphs.

Tables

Table …

#DBHangOps 07/10/14 -- MySQL Index Types and More!

Check out the recording below!

Hello everybody!

Join in #DBHangOps this Thursday, July, 10, 2014 at 11:00am pacific (18:00 GMT), to participate in the discussion about:

• Indexes in MySQL

  • PRIMARY, UNIQUE, FULLTEXT and more
  • Geo-spatial
  • Hash indexes
  • Fractal Indexes (TokuDB)

Be sure to check out the #DBHangOps twitter search, the @DBHangOps twitter feed, or this blog post to get a link for the google hangout on Thursday!

See all of you on Thursday!

Show notes

Indexes

Spatial index resources

• …

It was a year ago, on a nice Sunday night of the English Summer (apologies for the oxymoron), that Mark Riddoch came to see me and together we headed to the Vansittart Arms, our local family pub round the corner. A pint of London Pride on one side and a Honey Dew on the other were the perfect add-on to Mark’s MacBook Pro, on which Mark was showing me the 0.1 version of MaxScale. It was the result of the joint efforts of Mark’s team, Massimiliano and Vilho, who had worked hard to bring to life the first version of something that I believe will be a natural addition to clusters of MySQL/Percona/MariaDB servers in the near future.

A year ago, Mark showed me a …

With an ear to the interwebs, you’ll hear a few things about Docker. Docker is an open platform for developers and sysadmins to build, ship, and run distributed applications. In this blog post, I’m going to outline a very basic example of how to use Sphinx from within a Docker container. What is Docker? This [...]

Yay! My first blog post! As long as at least 1 person finds it useful, I’ve done my job. Recently, one of my long-term clients was noticing that while their INSERTs were succeeding, a particular column counter was not incrementing. A quick investigation determined the column was of type int(11) and they had reached the maximum value of 2147483647. We fixed this by using pt-online-schema-change to change the column to int(10) unsigned, thus allowing values up to 4294967295.

My client was now concerned about all his other integer-based columns and wanted me to check them all. So I wrote a quick-n-dirty script in Go to check all integer-based columns on their current value compared to the maximum allowed for that column type.

You …

MySQL Cluster enables high availability by storing data replicas on multiple hosts. MySQL Cluster maintains connections between data nodes by using high-speed interconnects over TCP/IP - standard or direct connections - or SCI (Scalable Coherent Interface) sockets.

To learn more about MySQL Cluster, take the MySQL Cluster training course.

This course is currently scheduled for the following locations:

After MySQL 5.1 was released work started on MySQL 5.2, but then this was renamed to MySQL 6.0. There were many new features introduced in 6.0. But then stabilizing this branch became as huge task. Eventually the decision was made to start of with a stable branch and backport the new features from 6.0. This is how many of the 6.0 features landed in 5.5 and 5.6.

So let's see which features 6.0 brought and were they landed. I'll use the What Is New in MySQL 6.0 section of the MySQL 6.0 Reference Manual for this.

• The Falcon storage engine. This never landed anywhere as far as I know. It's not even included in the …

Critical MySQL 5.6 bug: any user with GRANT privileges can unwillingly cause all replicas to break

The latest major release of MySQL brought us a lot of new and exciting features. As always, new features come with brand new bugs waiting to bite you in the least expected way.

I was implementing a monitoring system for a client and needed to create a new dedicated user. I went ahead and granted the usual basic privileges but later, I discovered that this user also needed the REPLICATION CLIENT privilege because the monitoring needed it to check for replication status.

No big deal, let’s grant this as well. Unfortunately I did not get it right at first:

grant replication client on database.* to user@’10.%';
ERROR 1221 (HY000): Incorrect usage of DB GRANT and GLOBAL PRIVILEGES

Ouch! My bad! This is a global privilege and I should grant it on “*.*”:

grant replication client on *.* to …

Managing many hosts is quite challenging task. There are many tools to solve the problem. My favorite is pdsh.

Running a command across a set of hosts is as simple as following:

# pdsh -w 192.168.177.[201-208] -R ssh reboot

Together with dshbak (which is a part of pdsh package) you can do even cooler things. Like, check which systems have yum:

# pdsh -w 192.168.177.[201-208] -R ssh "which yum" | dshbak -c
----------------
192.168.177.[201-203]
----------------
/usr/bin/yum 

Or which systems run older version of MySQL

# pdsh -w 192.168.177.[201-208] -R ssh "mysql -e \"SHOW VARIABLES LIKE 'version'\""  | dshbak -c
----------------
192.168.177.[201-203]
----------------
Variable_name   Value
version 5.6.19
----------------
192.168.177.[204-208]
----------------
Variable_name   Value
version 5.5.38

To make pdsh …