I had a great time last week at Percona Live, meeting up with lots of old friends, and getting to know lots of new ones.

It was great to meet many of the people that hang around on DBHangOps face to face. Geoff even got a community award (well done)! Unfortunately I had to miss the lunch.

It was also good to see Oracle getting a community award. Our engineers are extremely hard working, and all want to help community and customers alike be successful with their MySQL environments. There was lots of great positive attitude towards the work we’ve been doing, it was pleasing to hear that we are on the right track.

I haven’t been to a conference at that venue since the “old school” MySQL UC. Well done Percona for putting on such a great event.

And as a bonus, I even got to sit in front of Shlomi Noach on my flight from SFO to Newark: …

The heartbleed bug was introduced in OpenSSL 1.0.1 and is present in

• 1.0.1
• 1.0.1a
• 1.0.1b
• 1.0.1c
• 1.0.1d
• 1.0.1e
• 1.0.1f

The bug is not present in 1.0.1g, nor is it present in the 1.0.0 branch nor the 0.9.8 branch of OpenSSL some sources report 1.0.2-beta is also affected by this bug at the time of writing, however it is a beta product and I would really recommend not to use beta quality releases for something as fundamentally important as OpenSSL in production.

The bug itself is within the heartbeat extension of OpenSSL (RFC6520). The bug allows an attacker to leak the memory in up to 64k chunks, this is not to say the data being leaked is limited to 64k as the attacker can continually abuse this bug to leak data, until they are satisfied with what has been …

At MySQL, we have been working on simplifying the failover process
making it faster, more flexible and easier to use. In MySQL 5.6 we added
support for Global Transaction Identifiers (GTID), which was a huge leap in the
direction of easing the failover process hiding the details about
replication logs and positions. With MySQL 5.7.4, we are introducing a
new feature that further adds to flexibility and onliness- the user can
only shut down components that he needs to re-configure. 

What we allow with this new feature is to execute CHANGE MASTER TO
command without stopping slave altogether. We realized that stopping
slave altogether is not mandatory in all cases and doing that was more
of a cautious approach to switching master restricting more than what’s
required at times.

Lets dive deep into this to see what can be relaxed here. For this, lets …

The ‘uint3korr’ function inside of the mysqld server extracts a 3 byte unsigned integer from a memory buffer. One use is for ‘mediumint’ columns which encode their value in 3 bytes. MySQL 5.6 and MariaDB 10.0 claims to have optimized this function for x86 and x86_64 processors. There is a big comment that says:

Attention: Please, note, uint3korr reads 4 bytes (not 3)!
It means, that you have to provide enough allocated space.

The ‘uint3korr’ optimization may be fast, but it is not valgrind safe. Here is an example where valgrind detects TokuDB reading beyond the end of a buffer when it uses the ‘uint3korr’ function.

==3899== Thread 36:
==3899== Invalid read of size 4
==3899== at 0xB76C089: tokudb_uint3korr(unsigned char const*) (hatoku_defines.h:533)
==3899== by 0xB795C5E: cmp_toku_int(unsigned char*, unsigned char*, bool, unsigned int) (hatoku_cm
==3899== by 0xB797211: compare_toku_field(unsigned char*, unsigned char*, …

Considering last week was very rich in terms of announcements, we thought it might be useful to provide a summary of the information we shared, including the blogs from Oracle’s MySQL Engineers aggregated for easier access:

We sent out this press release last Monday to announce:

• The latest development milestone release of MySQL 5.7, 2x faster than MySQL 5.6 and 3x faster than MySQL 5.5
• The Release Candidate of MySQL Fabric, providing high availability management and scale out through sharding (included in the Release Candidate version of MySQL Utilities 1.4.2).
• The General Availability of MySQL Workbench 6.1, delivering additional capabilities for performance assessment and query optimization.
• Early access to features under development via labs.mysql.com including Geographic Information System (GIS), …

Sometimes, it is required to enable the general query log (which is disabled by default). If the general query log is enabled the server writes to this log information when clients connect or disconnect, and each SQL statement received from the client.

The question is, does enabling the general query log affects the MySQL performance ?
Also, it is possible to record the output of this log into either file or table in the mysql database (mysql.general_log), what is the performance impact of each one?

Let's do some simple benchmark for those scenarios to measure the actual impact on the mysql performance.

System Information:

HW configurations:

• CPU: Intel® Core™ i7-3520M Processor (4M Cache, up to 3.60 GHz).
  • 2 cores, 4 threads, HT enabled.
  …

After a four year hiatus, my participation in last week’s Percona Live MySQL Users conference marked my official return to the MySQL Community and Ecosystem. As with earlier renditions this year’s “UC” was very well attended with a healthy mix of familiar faces and new blood, all coming together to discuss, present and explore the boundaries of the most popular and widely used open source database on the planet.  There were many good, informative keynote and technical sessions, BoFs and the exhibit hall was packed most of the operating hours with those interested in what the MySQL ecosystem is up to.  I also found it very refreshing that Oracle was among the most active in presenting useful technical content around their current and future MySQL open source product releases. All in all, this year’s UC was very well done and as a Percona employee my …

Lean, mean MySQL and hulking Hadoop clusters may seem like an odd couple, but tying them together is now priority #1 for many MySQL users. This keynote talk on 1st day of this year's Percona Live MySQL Conference & Expo 2014 explores the data management trends spurring integration, how the MySQL community is stepping up, and where the integration may go in the future. Robert Hodges, CEO at

Next Wednesday, I will present a webinar about MySQL performance profiling tools that every MySQL DBA should know.

Application performance is a key aspect of ensuring a good experience for your end users. But finding and fixing performance bottlenecks is difficult in the complex systems that define today’s web applications. Having a method and knowing how to use the tools available can significantly reduce the amount of time between problems manifesting and fixes being deployed.

In the webinar, titled “Optimizing MySQL Performance: Choosing the Right Tool for the Job,” we’ll start with the basic top, iostat, and vmstat then move onto advanced tools like GDB, Oprofile, and Strace.

I’m looking forward to this webinar and invite you to join us April 16th at 10 a.m. Pacific time. You can learn more and also  …

Update: WordPress 4.2 has full UTF-8 support! There’s no need to upgrade manually any more. ?

For many years, MySQL had only supported a small part of UTF-8, a section commonly referred to as plane 0, the “Basic Multilingual Plane”, or the BMP. The UTF-8 spec is divided into “planes“, and plane 0 contains the most commonly used characters. For a long time, this was reasonably sufficient for MySQL’s purposes, and WordPress made do with this limitation.

It has always been possible to store all UTF-8 characters in the latin1 character set, though latin1 has shortcomings. While it recognises the connection between upper and lower case characters in Latin alphabets (such as English, French and German), it doesn’t recognise the same connection for other alphabets. For example, it doesn’t know …