You’ve just completed an upgrade from MySQL 5.5 to 5.6.  You followed the upgrade instructions in the manual, and ran mysql_upgrade.  But when you start MySQL 5.6, you still see the following error messages like the following in the server error log:

2013-03-26 16:45:51 5040 [ERROR] Column count of mysql.events_waits_current is w
rong. Expected 19, found 16. Created with MySQL 50520, now running 50610. Please
use mysql_upgrade to fix this error.
2013-03-26 16:45:51 5040 [ERROR] Column count of mysql.events_waits_history is w
rong. Expected 19, found 16. Created with MySQL 50520, now running 50610. Please
use mysql_upgrade to fix this error.

What went wrong?

Well, because mysql_upgrade is a client that’s built for a specific server version, it’s possible you have two …

Percona Server for MySQL version 5.6.11-60.3

Percona is glad to announce the first Release Candidate release of Percona Server 5.6.11-60.3 on June 3rd, 2013 (Downloads are available here and from the Percona Software Repositories).

Based on MySQL 5.6.11, including all the bug fixes in it, Percona Server 5.6.11-60.3 is the first RC release in the Percona Server 5.6 series. All of …

Many MySQL users are familiar with using slow query logs and tools such as mysqldumpslow to identify poor-performing SQL commands, and MySQL 5.6 introduces new powerful tools in PERFORMANCE_SCHEMA.  Both allow you to identify the date/time and the user account from which the command was issued, which is helpful – but if you’re using MySQL Enterprise Monitor (MEM), you can immediately identify the actual line of code responsible for the SQL command in question.  This happens to be one of my favorite and powerful features of MEM, but it’s frequently overlooked by new and experienced MEM users alike, so I’m writing the post to highlight it.

MySQL Enterprise Monitor, of course, is a commercial product that’s part of the MySQL Enterprise subscription.  But it’s freely-available under 30-day trial terms for evaluation from Oracle Software Delivery Cloud – if …

This is what I’m talking about, this is fantastic news! Anxiously looking forward to the WB 6.0 public Beta test phase for Mac / OS X…hopefully soon?

Over several blog posts, Tim has presented performance results on large data sets of TokuMX, our MongoDB product with fractal tree indexes integrated, side by side with MongoDB. Results look good. We’ve shown improved throughput numbers on a sysbench benchmark, faster load times, and high compression.

So what is TokuMX, and how does it achieve this performance?

TokuMX has replaced ALL of the storage code in MongoDB with fractal trees. Every collection, every secondary index, every metadata collection is stored with fractal trees, the same technology that implements the TokuDB storage engine for MySQL. That is, all data is stored and managed with our transactional, ACID and MVCC-compliant, write-optimized storage library.

TokuMX achieves …

On Friday I gave a presentation on “MySQL Query Patterns, Optimized” for Percona MySQL Webinars.  If you missed it, you can still register to view the recording and my slides.

Thanks to everyone who attended, and especially to folks who asked the great questions.  I answered as many as we had time for  during the session, but here are all the questions with my complete answers:

Q: Can you compare the use of subqueries/multiple joins vs. multiple queries (e.g. temp tables)?

For performance, it’s hard to make …

Back in November, I filed MySQL bug 67448, talking about a different type of max_allowed_packet problem.

See, an application had put data into the database, but could not retrieve it without getting max_allowed_packet. With the help of some really smart community folks (named Jesper Hansen, Brandon Johnson and Shane Bester), we determined that MySQL actually has 2 different max_allowed_packet settings: client and server.

When you change the max_allowed_packet variable, you are changing the server variable if it is in [mysqld] and the client variable if it is in [client] or [mysql] or whatever client you have. As far as we can tell, there’s no way to actually view what the client variable is, as looking at both the session and global max_allowed_packet variable shows you the server variable.

If max_allowed_packet is not set by the client, it defaults to …

I have never been to a DrupalCon before so my first was DrupalCon Portland 2013 (with some 3,500+ attendees). My first DrupalCon happened to also be one that I spoke at, and I hope to return to Austin in 2014 (added bonus: I’ve never been to Texas before).

SkySQL had decided to get a booth at DrupalCon since I was speaking and I have to say that the booth was very successful. You may ask why and the simple reasons are:

1. Everyone at DrupalCon was a user of MySQL. Once they hit scale, they may need professional services or even just switch to MariaDB. This is a captive audience.
2. Everyone running Drupal at scale with many modules and nodes generally faced issues with database slowdowns. Hello …

The MySQL for Developers course teaches you the knowledge, skills, tools and issues involved in writing applications with the MySQL database server. It forms the core of the MySQL Developer learning path.

During this 5-day course, you will perform lab work with Java and PHP, connecting to MySQL databases and executing queries and stored routines. Enrolling in this course will simultaneoursly help you prepare for the Oracle Certified Professional, MySQL Developer certification.

You can take this instructor-led course as a:

• Live-virtual event: Take this class live, from your own desk. No travel required. You can choose from a wide selection of events on the schedule to suit different timezones.
• In-class event: …

Hi Daniel,

Thanks for your comment. The function lock_get_mode() is declared as an inline function. Are you using optimized build? Also, in gdb, try the option "/4bt" instead of just "/4t" for the command "x". I think it is better to specify the size of the object explicitly.

Rgds,
anna