Please help me welcome a new member of the MySQL Community Team. Lenka Kasparova is based in Prague and joined Oracle with Sun acquisition in 2009-2010. She was the Project Manager for R&D on FP7 grant project AEGIS where she was responsible for the financial/administrative aspects as well as day to day project management activities. At Sun Lenka was part of the NetBeans acquisition and went through several positions from administrative, HR, and Project Management area… “Both Sun and Oracle gave me a great opportunity to learn a lot of things which I am happy to use in my new position.”

So please look for Lenka at next MySQL Community Team event near you!

Here is your chance to learn how this powerful relational database management system can make your life easier and more fun! The MySQL for Beginners class covers all the basics and will get you on your way, with a solid foundation. This instructor led, hands-on class covers the fundamentals of SQL and relational databases, using MySQL[tm] as a teaching tool.

You can take the MySQL for Beginners, 4 day instructor-led, class in any of the following three ways:

• Training-On-Demand: See what Ben Krug, MySQL Support Engineer has to say about his experience taking the MySQL for Beginners TOD. With this streaming video delivery, you get started on taking the MySQL for Beginners course within 24 hrs of purchase, and follow the course at your own pace.
• Live-Virtual-Class: Take …

Along with lots of new features in performance schema, a new summary table, event_statement_summary_by_digest, has been added to MySQL 5.6. This tables gives a consolidated view of different statements executed/executing on MySQL server.

WHAT IS DIGEST?
Digest is a hash calculated on normalized form of statement text which removes general property of a statement but keeps specific property. For ex. for two statements X and Y,

Removing general property means
normalized (X) == normalized (Y)
Preserving specific property after normalization means:
normalized (X) != normalized (Y)

On these normalized statement, a hash is calculated which is called DIGEST. So digest is a unique representation of statements having same structure.


Example :
SELECT 1 FROM t1; 
SELECT 2 FROM t1; 
Above two statements have same general structure …

This post is the following part #2 of the previous one - in fact Vadim's comments bring me in some doubts about the possible radical difference in implementation of AIO vs normal I/O in Linux and filesystems. As well I've never used Sysbench for I/O testing until now, and was curious to see it in action. From the previous tests the main suspect point was about random writes (Wrnd) performance on a single data file, so I'm focusing only on this case within the following tests. On XFS performance issues started since 16 concurrent IO write processes, so I'm limiting the test cases only to 1, 2, 4, 8 and 16 concurrent write threads (Sysbench is multi-threaded), and for AIO writes seems 2 or 4 write threads may be more than enough as each thread by default is managing 128 AIO write requests..

Few words about Sysbench …

I write a fair number of scripts on this site and have posted a lot of code over the years. Generally if I am not pasting the code to be viewed on the webpage then I link to a file that a user can download; which leads to a lot of mish-mash code that doesn’t have a home. I’ve always kept the code files in a private SVN repo over the years but have recently moved them all to BitBucket Git repositories. So here they are: lots of code samples and useful bits of programming to save time.

Generic Shell Scripts: https://bitbucket.org/themattreid/generic-bash-scripts/src
Generic Python Scripts: https://bitbucket.org/themattreid/generic-python-scripts/src
Generic MySQL Stored Procs: …

One of most easiest and preferred way of MySQL installation is binary installation. While performing mysql binary install using the below command, run into following errors.

[root@localhost mysql]# scripts/mysql_install_db --user=mysql
Installing MySQL system tables...
./bin/mysqld: error while loading shared libraries: libaio.so.1: cannot open shared object file: No such file or directory

Installation of system tables failed!  Examine the logs in
./data for more information.

To fix the problem, you have to install library (Kernel Asynchronous I/O (AIO) Support for Linux)

[root@localhost mysql]# yum install libaio                  [On CentOS]

After this mysql get installed successfully.

[root@localhost mysql]# scripts/mysql_install_db --user=mysql
Installing MySQL system tables...
OK
Filling help tables...
OK

To …

As many folks know, I do a bit of traveling, both going to conferences, and speaking at them (MySQL and others). So I have compiled a list of tips and tricks, from the basics like “do not forget to eat breakfast” to putting your business cards inside your bag. I have a list with pictures that I will add to as I think of more. I hope you enjoy this tumblr-style list of conference tips!

I've finally about finished up 1.2.4. Please give 1.2.4c1 a try. I plan to make the final release next week sometime.

1.2.4 will support Python 2.4, but it's not tested, and won't be supported in 1.3.0. Python 2.5, 2.6, 2.7 and PyPy are all tested and supported.

I still need to make some documentation updates. It turns out I can't easily make it work with Read The Docs since it has a C module, but I'm planning to have them online at packages.python.org.

We have seen number of issues with MySQL Server related to amount of memory you have in the system – these range from problems with large size Query Cache to bad drop table performance with large Innodb Buffer Pool size. As such I wonder how much memory do we really use to run MySQL Server these days ?

Note: There is a poll embedded within this post, please visit the site to participate in this post's poll.

Feel free to select multiple sizes if you have multiple kinds of instances in production and for boundary numbers please select the highest range which applies, ie for 16GB system select 16-64GB range. Thank you for your feedback ! I will keep the pool open until the end of the year when it will be frozen so we do not get results from multiple years mixed.

I’ll speak at the Central Virginia Ruby Enthusiasts group on Nov 13th. The topic is adaptive fault detection in MySQL servers. The techniques apply to any system for which you can measure throughput and concurrency, so come on out and learn how you can get rid of threshold-based monitoring!

Further Reading:

• Central Virginia MySQL Meetup has reached cruising altitude
• New Central Virginia MySQL Meetup
• Speaking at the Shenandoah Ruby Users …