Persistence Smoothie: Blending NoSQL and SQL – see user feedback and comments at http://joind.in/talk/view/1332.

Michael Bleigh from Intridea, high-end Ruby and Ruby on Rails consultants, build apps from start to finish, making it scalable. He’s written a lot of stuff, available at http://github.com/intridea. @mbleigh on twitter

NoSQL is a new way to think about persistence. Most NoSQL systems are not ACID compliant (Atomicity, Consistency, Isolation, Durability).

Generally, most NoSQL systems have:

• Denormalization
  
• Eventual Consistency
  
• Schema-Free
  
• Horizontal Scale
  

NoSQL tries to scale (more) simply, it is starting to go

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Most of this stuff is not PHP specific, and Python or Ruby or Java or .NET developers can use the tools in this talk.

The session on joind.in, with user comments/feedback, is at http://joind.in/talk/view/1320.

Slides are at http://talks.php.net/show/confoo10

“My name is Rasmus, I’ve been around for a long time. I’ve been doing this web stuff since 1992/1993.”

“Generally performance is not a PHP problem.” Webservers not config’d, no expire headers on images, no favicon.

Tools: Firefox/Firebug extension called YSlow (developed by yahoo) gives you a grade on your site.

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The DDL code paths for Drizzle are increasingly different from MySQL. For example, the embedded_innodb StorageEngine CREATE TABLE code path is completely different than what it would have to be for MySQL. This is because of a number of reasons, the primary one being that Drizzle uses a protobuf message to describe the table format instead of several data structures and a FRM file.

We are pretty close to having the table protobuf message format being final (there’s a few bits left to clean up, but expect them done Real Soon Now (TM)). You can see the definition (which is pretty simple to follow) in drizzled/message/table.proto. Also check out my

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In this month’s Database Journal piece we look at the spectrum of MySQL storage engines available, and examine what some of their strengths and weaknesses are.

View the article here: Survey of MySQL Storage Engines

In my last blog post, I showed how we can get some raw performance information from /proc into the MySQL database using a LOAD DATA INFILE (LDI) command.

I've modified that LDI call slightly to set the `other` column to equal the sum total of the CPU counters for those rows which begin with 'cpu'.

original:
other = IF(@the_key like 'cpu%', NULL , @val1);

new:
other = IF(@the_key like 'cpu%', user + nice + system + idle + iowait + irq + softirq + steal + guest, @val1);


Top provides a useful output that looks something like the following:

top - 04:59:14 up 14 days,  3:34,  1 user,  load average: 0.00, 0.00, 0.00
Tasks: 216 total,   1 running, 215 sleeping,   0 stopped,   0 zombie
Cpu(s):  0.0%us,  0.0%sy,  0.0%ni, 99.9%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:   8172108k total,  5115388k used,  3056720k free,   315180k buffers

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A couple of months ago (December 1st for those playing along at home) it marked five years to the day that I started at MySQL AB (http://www.mysql.com) (now Sun, now Oracle). A good part of me is really surprised it was for that long and other parts surprised it wasn’t longer. Through MySQL and Sun, I met some pretty amazing people, worked with some really smart ones and formed really solid and awesome friendships. Of course, not everything was perfect (sometimes not even close), but we did have some fun.

Up until November 2008 (that’s 3 years and 11 months for those playing at home) I worked on MySQL Cluster (http://www.mysql.com/cluster). Still love the product and love how much better we’re making Drizzle so it’ll be the best SQL interface to NDB :)

The ideas behind Drizzle

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In mysql we have — , /* and /*! comments.  This post is mainly about very basic c-style comments. /*! : C-Style comments in MySQL We normally see comments in MySQLdump as follows: /*!40000 ALTER TABLE `a` DISABLE KEYS */; Or /*!50013 DEFINER=`root`@`localhost` SQL SECURITY DEFINER */ These are actually C-Style comments which has embeded sql and treated specially [...] Related posts:

Calculate Mysql Memory Usage – Quick Stored Proc

MySQL Memory Usage Limits on 32 bit Linux

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After seeing quite some SQL statements over the years, something is bugging me: there is no consistent convention as for how to write an SQL query.

I’m going to leave formatting, upper/lower-case issues aside, and discuss a small part of the SQL syntax: table aliases. Looking at three different queries, I will describe what I find to be problematic table alias use.

Using the sakila database, take a look at the following queries:

Query #1

SELECT
 R.rental_date, C.customer_id, C.first_name, C.last_name
FROM
 rental R
 JOIN customer C USING (customer_id)
WHERE
 R.rental_date >= DATE('2005-10-01')
 AND C.store_id=1;

The above looks for film

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As I'm sure everyone has figured out by now, I've joined Rackspace where I will continue to work on Drizzle. I'm honestly thrilled with my new home, and there are a myriad of reasons for that. I think the one that I'm most excited about is that they are already the thing that all of the hype was about MySQL and RedHat and IBM wanting to become: A Service Company Rackspace doesn't want you to run Rackspace-Apache or RackspaceDB or EC-Rackspace. They want you to be able to run bog-standard Apache. And Linux. And MySQL. And PHP. And Drizzle. Then, Rackspace wants to be the best at providing you the service you need around those. No ludicrous MySQL Enterprise "we'll sell you a license to a free product, and then we'll include bundled with that a subscription a piece of non-free monitoring software" upselling. Rackspace actually wants to provide you a valuable  [Read more...]

Giving a talk at the University of Utah on everything from scaling, clustering, mysql, mysql internals, noSQL (Cassandra) to how to manage all this stuff. If you are there at University I'm bringing some Swag!

Also I will upload the slides and put them here.

In response to Mark Callaghan’s post mk-schema-change.

I apologize for not commenting on the post itself, I do not hold a Facebook account. Anyway this is a long write, so it may as well deserve a post of its own.

Some of the work Mark is describing already exists under openark kit’s oak-online-alter-table. Allow me to explain what I have gained there, and how the issue can be further pursued. There is relevance to Mark’s suggestion.

oak-online-alter-table uses a combination of locks, chunks and triggers to achieve an almost non-blocking ALTER TABLE effect. I had a very short opportunity to

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I've been doing Google Summer of Code projects with students since its creation. As far as intern programs go, it has been one of the most successful I have ever worked with.

Last year was particularly awesome in that with Drizzle we were able to have students work on projects that made it back into Drizzle. While I have always seen good work created, it has always been hit or miss on whether the student's work has made it back into the project. Last year though we got more code in then ever before and I believe this year will be the same. We have had students go on to jobs thanks to the work they did on Drizzle.

Interning gives you real experience, and it provides resume material which differentiates students who are going on to work in the software engineering field. Working on open source means that you have real



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Working on mycheckpoint, I have the intention of adding custom monitoring. That is, letting the user define things to monitor. I have my own thoughts, I would be grateful to get more input!

What would the user want to monitor?

Monitoring for the number of SELECT statements per second, InnoDB locks, slave replication lag etc. is very important, and monitoring utilities provide with this information. But what does that tell the end user? Not much.

The experienced DBA may gain a lot. The user would be more interested in completely other kind of information. In between, some information is relevant to both.

Say we were managing an on-line store. We want to monitor the health of the database. But the health of the database is inseparable from the health of the application. I mean, having little to no disk usage is fine,

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System administrators familiar with the Linux operating system use the tools in the 'procps' toolset all the time. Tools which read from /proc include top, iostat, vmstat, sar and others. The files in /proc contain useful information about the performance of the system. Most of the files are documented in the Linux kernel documentation. You can also check man 5 proc.

Most performance monitoring tools invoke other tools like iostat to collect performance information instead of reading from the /proc filesytem itself. This begs the question, what can you do if you don't have access to those tools? Perhaps you are using a hosted Linux database and have no access to the underlying shell to execute tools like iostat or top? How could you gather information about the performance of the actual system without being

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