I've made a patch that makes EXPLAIN show conditions that are attached to various points of the query plan. If you run EXPLAIN CONDITIONS (or EXPLAIN CONDS) statement, the output besides the usual EXPLAIN resultset will have a second resultset that will show

• Conditions attached to individual tables
• Conditions that are applied before/after join buffering
• Table and index conditions that were pushed down into the storage engine
• ... and so forth (I believe it prints out all possible conditions that are there)

It looks like this:

mysql> explain conds select * from City, Country where City.Country=Country.Code and City.Name like 'C%' and Country.Continent='Asia' and Country.Population>5000000;
+----+-------------+---------+------+-------------------+-----------+---------+-----------------+------+------------------------------------+
| id | select_type | table   | type | …

Tuning MySQL Performance with MySQLTuner

MySQLTuner is a Perl script that analyzes your MySQL performance and, based on the statistics it gathers, gives recommendations which variables you should adjust in order to increase performance. That way, you can tune your my.cnf file to tease out the last bit of performance from your MySQL server and make it work more efficiently.

If there is one thing that I terribly miss after moving to this country, that would be the variety of Mangoes in India. I've been asked at the United States Customs if I'm importing any mangoes. The fruit's flavor, fragrance and color is just great so I don't blame them at all. There is even International Mango Festival conducted every year since 1987 in Delhi. The festival features more than 550 varieties for visitors to view and taste.

I can talk at lengths about the fruit Mango but this entry is about Mango*. So what is it ?

Tuning MySQL Performance with MySQLTuner

MySQLTuner is a Perl script that analyzes your MySQL performance and, based on the statistics it gathers, gives recommendations which variables you should adjust in order to increase performance. That way, you can tune your my.cnf file to tease out the last bit of performance from your MySQL server and make it work more efficiently.

Some months ago I helped out in another project in which they had some performance problems. They had a very big table and the index of the table was bigger than the table itself. As every change in the table causes MySQL to recalculate/reload the index, this can take some seconds for such big tables.
So, I thought it would be a good idea to split that big table into very small ones. This should reduce the overhead of reloading big indices and instead reload only very small parts. And the next thought was: Is it possible to use the "new" MySQL-Partitioning for that?
Continue reading "Is MySQL-partitioning useful for very big real-life-problems?"

Lets start a mysqld instance on a host machine :

bash-3.1$ ./mysql/libexec/mysqld --defaults-file=./mysql/etc/my.cnf
080902 11:55:50 [Warning] option 'thread_stack': unsigned value 65536 adjusted to 131072
080902 11:55:50 [Note] Event Scheduler: Loaded 0 events
080902 11:55:50 [Note] ./mysql/libexec/mysqld: ready for connections.
Version: '5.1.24-rc'  socket: '/tmp/mysql_9090.sock'  port: 9090  Source distribution

As you can see I have used 'defaults-file' option to specify the options file to the
server. This is to avoid the conflict if there are more mysqld instances running on the
same machine.
So, MySQL server is up and running and listening to port 9090 as specified in my.cnf file.

Note : Default port for mysqld is 3306.

Now, we can try connecting to this server both locally as well as remotely.

…

Lets start a mysqld instance on a host machine :

bash-3.1$ ./mysql/libexec/mysqld --defaults-file=./mysql/etc/my.cnf
080902 11:55:50 [Warning] option 'thread_stack': unsigned value 65536 adjusted to 131072
080902 11:55:50 [Note] Event Scheduler: Loaded 0 events
080902 11:55:50 [Note] ./mysql/libexec/mysqld: ready for connections.
Version: '5.1.24-rc'  socket: '/tmp/mysql_9090.sock'  port: 9090  Source distribution

As you can see I have used 'defaults-file' option to specify the options file to the
server. This is to avoid the conflict if there are more mysqld instances running on the
same machine.
So, MySQL server is up and running and listening to port 9090 as specified in my.cnf file.

Note : Default port for mysqld is 3306.

Now, we can try connecting to this server both locally as well as remotely.

…

Hi,

We are planning a series of live webinars for the time slot which is convenient for APAC regions.

Have you concerned scalability or performance of MySQL in a production environment at a fast-growing company? Then, this is a chance to learn MySQL more! This series of webinars consists of four webinars which will explain MySQL features and resolve such concerns. Each webinar will introduce actual case studies and best practices to drive your understandings on MySQL. Also we will include descriptions on relative MySQL Enterprise purchase options at the end.

Planned Webinar Topics

1. High Availability/Scalability
2. Clustering
3. Monitoring/Backup/Recovery
4. Performance

*The above topics are subject to change.

1st Webinar Schedule

“MySQL High Availability/Scalability Solutions”

For the enterprise …

Gnu is 25 years. How time flies...

I still remember my first contact with the free software people at the Stockholm-Helsinki cruise 1991 (where Minix was first released).

I was back then, of course, already an emacs and gcc user, but that trip was when I first felt an urge to release something as free software. (The concept 'open source' didn't exist back then). It did however take me until 1995 before David and I felt we had something that was good enough to be released.

We haven't yet achieved world domination in all categories, but we are definitely getting there; Some things take time, but we have time on our side.

As a way to celebrate, the actor and humorist Steven Fry has made a video entitled 'Happy Birtday to Gnu'. Please check it out!

Happy birthday to Gnu!

Our goal at Continuent is to be the go-to guys for database scale-out. Last Thursday we opened up a new community site for scale-out software at http://community.continuent.com. The site is driven by Joomla and has a number of very nice additions like Fireboard Forums and Mediawikis for each project. The first day or two was a bit bumpy as we nailed down some final issues, but most features are now working. We hope the result will be a nice place to meet other people who are interested in database scale-out and share ideas as well as software.

As you will see when visiting the community site, we have a variety of projects that we collectively call the Tungsten Scale-Out Stack. We have had this …