PlanetMysql.ru — информация о СУБД MySQL

Some time ago I wrote in Russian language guide for finding errors in SQL application.

To be honest I wrote it having personal aim to have a text which I can easily use refer in case of user questions about how to find particular thing. But this makes less sense having no English version. So now I started to translate it to English and publish. Introduction and first chapter are ready.

You can find it at http://sql-error.microbecal.com/en/index.html  Comments and corrections of mistakes are welcome here.

This blog post is just to list links and tips on getting home to Finland.

First leg: getting to anywhere in Europe

Being stuck in San Fransisco, my first problem has been to get just anywhere closer to home. Taking a boat from America to Europe takes from 6-15 days and is not significantly cheaper than flying. So the best bet is just to fly to Europe.

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I've been working in a fully distributed work environment for almost 8 years now (I joined MySQL AB in April, 2002). Therefore I've been reading Toni Schneider's blog post about the "5 reasons why your company should be distributed" with great interest – he raised several points that I fully agree with and which I covered in my talks about "Working for a virtual company - how we do it at MySQL" at last year's next09 conference (slides, video) and at FrOSCon 2009 (video).

However, Toni draws a profusely positive picture here, or, as my dear colleague Dean pointed out "The blog overly simplifies the realities of a distributed workforce, making it sound like it's all ponies and rainbows".

SilverStripe is a open source content management system(CMS) to create and
maintain website, it is currently published to the OpenSolaris /contib repository.

Installation of SilverStripe on OpenSolaris is straightforward by simply clicking
the installation button on the silverstrip's 'install.php' page,
however, the installation didn't work complaining with mysql query
execution failed:

"[User Error]  Couldn't run query: SELECT `SiteTree_Live`.*,
`GhostPage_Live`.*, `ErrorPage_Live`.*, `RedirectorPage_Live`.*,
`VirtualPage_Live`.*, `SiteTree_Live`.ID,
if(`SiteTree_Live`.ClassName,`SiteTree_Live`.ClassName,'SiteTree') AS
RecordClassName FROM `SiteTree_Live` LEFT JOIN `GhostPage_Live` ON
`GhostPage_Live`.ID = `SiteTree_Live`.ID LEFT JOIN `ErrorPage_Live`
ON `ErrorPage_Live`.ID = `SiteTree_Live`.ID LEFT JOIN
`RedirectorPage_Live` ON `RedirectorPage_Live`.ID =
`SiteTree_Live`.ID LEFT JOIN `VirtualPage_Live` ON
`VirtualPage_Live`.ID = `SiteTree_Live`.ID WHERE
(`SiteTree_Live`.`ParentID` = 1 AND `SiteTree_Live`.ID != 1 AND
ShowInMenus = 1) ORDER BY Sort Lost connection to MySQL server during
query”

Running the same query within the MySQL client get the error of MySQL server
crash:

ERROR 2013 (HY000): Lost connection to MySQL server during query

It was caused by MySQL's bug: #44538 , the same problem as Joomlar! with MySQL explained
clearly in Georg's blog. To solve this problem, I enabled the 64-bit MySQL service
on OpenSolaris:

svccfg -s mysql:version_51 setprop mysql/enable_64bit=true
svcadm refresh mysql:version_51
svcadm restart mysql:version_51

The SilverStripe installation succeed without the problem after using the
64-bit MySQL 5.1.

October, 8 I did master-class about catching error in SQL application at PHPConf 2009. Who speaks Russian can get slides here: pdf and odp.

There were several things which were interesting for me during my talk.

First is interaction with audience of different educational (or better to say MySQL practice) level. I should make a note for feature how to solve moments when 1/3 of audience listens carefully and is just right for the talk, another 1/3 knows things I am talking at the moment already and last 1/3 needs explanations of basic things such as what is difference between table-level and row-level locks. Probably I should create list of things user should know before attend the talk.

It was surprising how many people don't use SHOW ENGINE INNODB STATUS and InnoDB Monitor! And I had very little information about these topics in my talk.

Last thing was my expectation about classroom with desks and people with laptops on it. I saw no desks and 1-2 laptops for more than 50 people. Next time I should create interactive program without need of laptop. Like quiz or so.

This Thursday (October 15th, 13:00 UTC), Giuseppe Maxia will present the Spider Storage Engine. Here's from the abstract: Everybody needs sharding. Which is not easy to maintain. Being tied to the application layer, sharding is hard to export and to interact with. The Spider storage engine, a plugin for MySQL 5.1 and later, solves the problem in a transparent way. It is an extension of partitioning. Using this engine, the user can deal transparently with multiple backends in the server layer. This means that the data is accessible from any application without code changes. This lecture will briefly introduce MySQL partitioning, and then show how to create and use the Spider engine, with some practical examples. The talk covers the latest version of the Spider engine, which includes a condition pushdown feature that increases performance significantly.

For MySQL University sessions, point your browser to this page. You need a browser with a working Flash plugin. You may register for a Dimdim account, but you don't have to. (Dimdim is the conferencing system we're using for MySQL University sessions. It provides integrated voice streaming, chat, whiteboard, session recording, and more.) All MySQL University sessions are recorded, that is, slides and voice can be viewed as a Flash movie (.flv). You can find those recordings on the respective MySQL University session pages which are listed on the MySQL University home page.

MySQL University is a free educational online program for engineers/developers. MySQL University sessions are open to anyone, not just Sun employees. Sessions are recorded (slides and audio), so if you can't attend the live session you can look at the recording anytime after the session.

Here's the schedule for the upcoming weeks:

• October 22: Dual Master Setups With MMM (Arjen Lentz)
• October 29: MySQL scalability on SPARC & INTEL X5500 (Nehalem) (Benoit Chaffanjon)
• November 12: Gearman for MySQL (Giuseppe Maxia)
• November 19: memcached Functions for MySQL (UDFs) (Patrick Galbraith)
• December 3: Practical Full-Text Search in MySQL (Bill Karwin)

The schedule is not engraved in stone at this point. Please visit http://forge.mysql.com/wiki/MySQL_University#Upcoming_Sessions for the up-to-date list. On that page, you can also find the starting time for many time zones.

You can do all sorts of magic with LVM, like backing up MySQL using file system snapshots, but in order to do so you need to set it first. When installing a new computer with Suse Linux I found that this was harder than expected, unless you know what to do. Needless to say, I didn't, but some friends gave me a hand on IRC, and now I do. :-)

So I wrote a little article about this which you can find here, in an effort to save others some time. The article is about setting up LVM with Suse Yast, but you can probably use it for other flavors of Linux, too.