LinkedIn has what they call "inDays" where employees may so something interesting which may not be directly related to their day job. I spent my inDay by porting my old WL820 project (External Language Stored Procedures) to MariaDB 5.3.
The code, as usual, is available on LaunchPad ... To get the branch, simply do:
bzr branch lp:~atcurtis/maria/5.3-wl820 The test cases pass... I haven't tested
Cleaning DataDuplicate keys happen. I see it most when you
feed data into a database and the source data is dirty.
Source data is usually dirty, that's why they want it in a
database.
The UNIQUE constraint clause in SQL prevents duplicate keys from
ever getting into your pristine database--at least in
theory. Sometimes a plain old attribute just needs to be
turned into a key for some "practical" reason.
A common data cleaning need is finding and removing duplicate
keys. Don't forget to turn on unique constraints for your
newly clean keys when you are ready. You never know when
you might get hit by a drive-by data sludger.
Finding Duplicate KeysSELECT my_key, count(*) FROM my_table GROUP
BY my_key HAVING count(*) > 1;
Remove Duplicate KeysDELETE
FROM tableA
WHERE uniquekey NOT IN
(SELECT …
I don’t think there is a single good-quality MySQL init script for a Unix-like operating system. On Windows, there is the service facility, and I used to write Windows services. Based on that, I believe Windows has a pretty good claim to better reliability for start/stop services with MySQL. What’s wrong with the init scripts? Well, let me count the reasons! Wait, I’m out of fingers and toes. I’ll just mention the two annoying ones that I’ve run into most recently.
A good day for MySQL at COLLABORATE 12. Most of the sessions had
good attendance. Dave and I also got the pleasure of
meeting Michael McLaughlin of BYU. He is also an
Oracle ACE in Database App Development.
Michael is a support of Oracle and MySQL and I have just recently
added his blog to the Planet site.
This is an important feature and security release.
Bugfixes:
New experimental features:
A few weeks ago I blogged about the HTTP JSON api in Drizzle. (See also a small demo app using it.) In this post I want to elaborate a little on the design decisions taken. (One reason to do this is to provide a foundation for future work, especially in the form of a GSoC project.)
Looking around: MongoDB, CouchDB, Metabase
Yesterday (4/19) I attended the AWS Summit in NYC (http://aws.amazon.com/aws-summit-2012/nyc).
I'm a big fan and also a heavy user of AWS especially S3, EC2,
and naturally, RDS. In every point in time I have several dozens
of AWS machines running for me out there in the East region, and
in some cases when we do some special benchmarks and tests,
number of EC2 and RDS machines can easily reach 3-digit. As I
said, I'm a fan...
A few quotes I was able to catch and document on my laptop, on my
laps...:
"When you develop an app for facebook, you must be prepared (and
be afraid) that to your party, not noone will show up, but
everybody will show up!" So true! Simple and true. We all want to
succeed, to have success with our app. We have to think about
scaling from day 1.
"Database was bottleneck for building of sophisticated apps. This
is …
There are a few ways to implement counters. Even though it’s not a complex feature, often I see people having problems around it. This post describes how bad implementation can impact both application and MySQL performance and how to improve it.
A customer asked me for help with performance problem they were facing. I logged into their database and found many client connections waiting for table locks. Almost all threads were stuck on one, small table called hits. What was the reason?
The problem was related to the way they developed a very simple system for counting page views they later used in some reporting. The table structure was:
mysql> SHOW CREATE TABLE hits\G *************************** 1. row *************************** Table: hits Create Table: CREATE TABLE `hits` ( `cnt` int(11) NOT NULL ) ENGINE=MyISAM mysql> SELECT * FROM hits; +---------+ | cnt | +---------+ | 3823273 | +---------+
…
[Read more]This post is about a fairly technical detail of how Galera works. I'm writing it down in preparation for testing this feature so that I can agree with Alex whether to file a bug or not. I'm sharing it on my blog just in case someone else might benefit from learning this.
Galera 2.0 introduces rolling schema upgrades. This is a new way to do non-blocking schema changes in MySQL.
As the name suggests, it is done as a rolling upgrade. Having seen clusters doing rolling upgrades before, I assumed this is what happens:
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