SHOW PROFILES shows how much time MySQL spends in various phases of query execution, but it isn’t a full-featured profile. By that, I mean that it doesn’t show similar phases aggregated together, doesn’t sort them by worst-first, and doesn’t show the relative amount of time consumed. I’ll profile the “nicer_but_slower_film_list” included with the Sakila sample [...]
Optimize Your SQL With Percona’s Online Query Advisor!
February 15, 2012 By 23 Comments
Wouldn’t it be nice if you could get expert advice on your SQL queries to find problems in them, the same way that programmers can use lint-check tools to warn about bugs in their C? if ( execute = 1 ) { launch_missile(); } Such a simple mistake, but it’s the kind of thing that [...]
linux.conf.au 2012 roundup
January 24, 2012 By Leave a Comment
I spent last week at linux.conf.au in Ballarat, Victoria (that’s the Victoria in Australia, not wherever else there may be one) which is only a pleasant two hour drive from my home town of Melbourne (Australia, not Florida). I sent an email internally to our experts detailing bits of the conference that may interest them [...]
MySQL Training in Frankfurt, Germany
December 27, 2011 By Leave a Comment
We will be holding our highly acclaimed MySQL workshops in Frankfurt, Germany the week of February 13th. Early registration is open; enroll today and secure your seat. Detail and enrollment can be found here.
MySQL Training in Washington, DC
December 13, 2011 By Leave a Comment
Many of you have seen the announcement for our Percona Live in Washington, DC in January! But did you know we also have our highly rated MySQL Training coming to Washington, DC the week of January 16h? Full details can be found on the Percona website. If you would like to attend the MySQL Training, click here [...]
When Does InnoDB Update Table Statistics? (And When It Can Bite)
October 6, 2011 By 5 Comments
An InnoDB table statistics is used for JOIN optimizations and helping the MySQL optimizer choose the appropriate index for a query. If a table’s statistics or index cardinality becomes outdated, you might see queries which previously performed well suddenly show up on slow query log until InnoDB again updates the statistics. But when does InnoDB [...]
SELECT UNION Results INTO OUTFILE
September 14, 2011 By Leave a Comment
Here’s a quick tip I know some of us has overlooked at some point. When doing SELECT … UNION SELECT, where do you put the the INTO OUTFILE clause? On the first SELECT, on the last or somewhere else? The manual has the answer here, to quote: Only the last SELECT statement can use INTO [...]
Explaining Indexes with a Library Metaphor
August 30, 2011 By 1 Comment
My favorite metaphor for explaining indexes is comparing them to index cards in an old library. In an old library, you used to (or still do) have index cards at the front desk which have some brief description of the books in the library. They also used to be categorized alphabetically. (image taken from http://www.flickr.com/photos/reedinglessons/2239767394/) [...]
Preprocessing Data
August 8, 2011 By 3 Comments
There are many ways of improving response times for users. There are some people that spend a lot of time, energy and money on trying to have the application respond as fast as possible at the time when the users made the request. Those people may miss out on an opportunity to do some or [...]
MySQL at Facebook, present and future
April 25, 2011 By Leave a Comment
Harrison Fisk, from the Facebook database team, will be in New York City delivering the closing keynote at Percona Live next month. He’ll be talking about the present status and future plans for MySQL inside Facebook’s environment. As you probably know, Facebook is one of the largest users of MySQL, with their own set of [...]
