I recently wrote a post about inner and outer joins, and a couple of people asked what the difference is between USING and ON.

In a nutshell, you use ON for most things, but USING is a handy shorthand for the situation where the column names are the same.

Consider this example dataset:

mysql> select * from pets;
+---------+---------+--------+-----------+
| pets_id | animal  | name   | owners_id |
+---------+---------+--------+-----------+
|       1 | fox     | Rusty  |         2 |
|       2 | cat     | Fluffy |         2 |
|       3 | cat     | Smudge |         3 |
|       4 | cat     | Toffee |         3 |
|       5 | dog     | Pig    |         3 |
|       6 | hamster | Henry  |         1 |
|       7 | dog     | Honey  |         1 | …

I recently wrote a post about inner and outer joins, and a couple of people asked what the difference is between USING and ON.

In a nutshell, you use ON for most things, but USING is a handy shorthand for the situation where the column names are the same.

Consider this example dataset:

mysql> select * from pets;
+---------+---------+--------+-----------+
| pets_id | animal  | name   | owners_id |
+---------+---------+--------+-----------+
|       1 | fox     | Rusty  |         2 |
|       2 | cat     | Fluffy |         2 |
|       3 | cat     | Smudge |         3 |
|       4 | cat     | Toffee |         3 |
|       5 | dog     | Pig    |         3 |
|       6 | hamster | Henry  |         1 |
|       7 | dog     | Honey  |         1 | …

Join me Wednesday for a free webinar on using the new Percona Toolkit v2.0.3 to verify replication integrity. If you’re not familiar with this topic, it’s one of those must-do things that no one officially tells you is necessary with MySQL. The new tools in Percona Toolkit 2.0.3 make it much easier and less complicated — and safer — than before. Well worth an hour of your time.

Further Reading:

• Free webinar on preventing MySQL downtime
• Free webinar on MySQL performance this Thursday
• …

MySQL High Availability RealizedJoin us on Tuesday, January 24th at 6:30 pm ETNYC Seminar & Conference Center71 West 23rd St. (corner of 6th Ave.), Suite 515/Lower Level, New York, NYEdward Archibald, CTO at Continuent, will go through a detailed case study to show you how you can start with the MySQL version/build (MySQL Community 5.x, MySQL Enterprise 5.x, MariaDB, Percona, etc.), along with

Nice one ... thank you :)

Today I’m working on integrate the Percona toolkit (instead of maatkit) in my own tools and I’m playing with pt-query-digest and pt-query-advisor.
These tools can be very interesting to identify some queries from established rules.
The  –review option is available for two of them and helps me to store a sample of each class of query and match them with an advice.

The rules (or advices) are available in the pt-query-advisor documentation and let you identify various problems such as queries with an argument with leading wildcard or with a table joined twice, for example.
There are 3 types of rules : note, …

Nice one ... thank you :)

Join me Wednesday for a free webinar on using the new Percona Toolkit v2.0.3 to verify replication integrity. If you’re not familiar with this topic, it’s one of those must-do things that no one officially tells you is necessary with MySQL. The new tools in Percona Toolkit 2.0.3 make it much easier and less complicated – and safer – than before. Well worth an hour of your time.

If you're in the City of Angles this week, be sure to stop by the Southern California Linux Expo (SCALE) - the largest annual Linux, Open-Source, and Free Software conference held in Los Angeles.  Join SkySQL and its strategic partner, Monty Program, January 20-22, at the Hilton Los Angeles Airport hotel. Stop by our booth, #65, and meet our team. As well, don't miss our talks on MySQL & MariaDB:

• The MySQL Storage Engines Landscape - Colin Charles, Monty Program, Friday, 1/20, 11:30AM

• A Closer Look at MySQL Cluster:  An Architectural Overview - Max Mether, SkySQL, Friday, 1/20, 4:00PM

• MariaDB:  The New M in Lamp - Colin Charles, Monty Program, Friday, 1/20, 5:00PM

If you haven't …

The best way to run pt-query-digest is by making absolutely sure it is not running on any server that is even slightly important to production.

I recently had a case where pt-query-digest took up all the memory and swap on a (linux) development server. I think the reason was that the slow log had blob data in it.
Even though it wasn't a production server, it managed to upset some people.


So I:

1. Installed strawberry perl on my windows computer
2. Downloaded the gzip'd slow log file (using WinSCP)
3. Unzip'd it
4. Saved percon.com/get/pt-query-digest to a .pl file on my laptop
5. Went …