Recently I had a chance to take a look at Redis project, which is semi-persistent in memory database with idea somethat similar to memcache but richer feature set.

Redis has simple single process event driven design, which means it does not have to deal with any locks which is performance killer for a lot of applications. This however limits it scalability to single core. Still with 100K+ operations a second this single core performance will be good enough for many applications. Also nothing stops you from running many Redis instance on single server to get advantage of multiple cores.

I call Redis semi-persistent because it does not store the data on disk immediately but rather dumps its all database every so often - you have a choice of configuring time and number of updates between database dumps. Because dump is basically serial write Redis does not an expensive IO …

Code scanning and management vendor Black Duck reports the GNU General Public License v2 (GPLv2) now dipping below 50% share of open source software. While we already knew that GPLv2 was somewhat in decline from its far greater share of open source code over the last 5-10 years, it is useful to know what pool of code we’re talking about. We must also remember that while GPLv2 may not be as dominant as it once was and that other licenses, particularly GPLv3, are quickly gaining share, GPLv2 is still quite relevant to enterprise open source software, is used in a variety of newer and popular applications across the enterprise stack and is likely to remain in the top 10 licenses for a long time.

Regarding GPLv2 and Black Duck’s findings, some folks are rightly asking what code and how much of it are we considering where GPLv2 accounts for half or less of the …

OK, yeasterday I published a post where I complained about the complexities of Drag-and-Drop in plain C on Windows, and how this was related to Object Orientation gone bad. Why do you need three or 4 objects, jsut to drag a string of text from one place to another?

Well, then, if you agree that this is outrageous, I have help for you now. I just published my plain C library that does just this. You simple Win32 C program need not worry about OLE or COM. About IDataObject or interfaces or any of that stuff. Just usse hardcore C, like all macho developers like myself do. You need my library though, and I admit I AM cheating a bit in it, but actually, it does the trick and it follows the rules, both from COM/OLE and Win32 points of views.

Now, to drag and receive a text string, you need my library and …

A colleague at work asked me “how can I run a case sensitive select on a case insensitive table?” out of curiosity and for a moment I hesitated, then said, yeah why not :) ….

Below are two different approaches (one of which is quite inefficient) and if anyone has another way, better or worse, please do leave a comment with your suggested approach :).

Cheers,
Darren

Preparation


mysql [localhost] {root} (test) > create table t1(a varchar(20));
Query OK, 0 rows affected (0.02 sec)

mysql [localhost] {root} (test) > insert into t1 (a) values ('darren');
Query OK, 1 row affected (0.00 sec)

mysql [localhost] {root} (test) > insert into t1 (a) values ('Darren');
Query OK, 1 row affected (0.00 sec)

mysql [localhost] {root} (test) > insert into t1 (a) values ('DarRen');
Query OK, 1 row affected (0.00 …

Hi all,

The past few months, I've been developing a course on the concepts of cloud computing and virtualization. It's coming along very well, and this week I've been working on a demo for an application in the cloud that uses a database located elsewhere in the cloud (i.e. on another virtual server). I'd thought I share the steps with you. I used MySQL, but the steps should be similar for other databases.

1. Install MySQL on the server.
2. Create a new user for MySQL: create user USERNAME identified by 'PASSWORD';
3. Grant the user access to the database: grant all privileges on DATABASE.* to USERNAME identified by 'PASSWORD';
4. Then I started up the IDE and went to the Services window, where I connected to my local MySQL database.
5. After connecting, I right-clicked the MySQL driver node and chose Connect Using.
   The New Database Connection dialog box …

Hi all,

The past few months, I've been developing a course on the concepts of cloud computing and virtualization. It's coming along very well, and this week I've been working on a demo for an application in the cloud that uses a database located elsewhere in the cloud (i.e. on another virtual server). I'd thought I share the steps with you. I used MySQL, but the steps should be similar for other databases.

1. Install MySQL on the server.
2. Create a new user for MySQL: create user USERNAME identified by 'PASSWORD';
3. Grant the user access to the database: grant all privileges on DATABASE.\* to USERNAME identified by 'PASSWORD';
4. Then I started up the IDE and went to the Services window, where I connected to my local MySQL database.
5. After connecting, I right-clicked the MySQL driver node and chose Connect Using.
   The New Database Connection dialog box …

After the slow down due to vacation and warm weather we are ready for a series of educative Italian webinars on MySQL. Here is the list:

Semptember 10@10am CET - "Top 5 Tuning tips for MySQL"
Are your applications slow during peak times? Is the database running slowly? Do you find difficult to pinpoint performance problems? Then this webinar is for you!I will cover the top 5 tips to speed up your MySQL databases from a developer as well as DBA point of view.

October 8@10am CET - "Introduction to MySQL for Windows"
Do you know that MySQL is used extensively on Windows? Would you like to learn the tools that we provide?
Join this webinar! We will discuss the advantages of using MySQL on the …

Last week we ended the first Monty Program Ab company meeting in Mallorca, Spain. Even if many of us have met before, there are a couple who had not met everyone before and it was great to be together. Even for myself, since I was in the Sales org at MySQL and Sun, I wasn't that close with all the oldtime developers, so it was great to finally spend several days with them.

Since it was the first meeting both for the company and MariaDB project, we spent a lot of time on the "vision, strategy" excercises. Btw, for future MariaDB meetings we will in the future always invite all the Maria Captains and other community members, it is not intended to be a meeting of one company at all. For this meeting, we had 3 non-employees present and they gave valuable input, so it already works, even if we will do more of it in the future.

…

Last week on the train to Seattle I was hacking on the new libdrizzle protocol plugin when realized I could really use a debugging console that did not require any socket communication. Since I abstracted a Client plugin in the server (Protocol class for the MySQL folks), this can easily be done by just writing a new plugin. I needed to do some refactoring with the listener plugin to not require a TCP socket/accept and instead poll any arbitrary file descriptor. This allows the the Listen plugin to create the client instance any way it wants. After a bit of hacking and cleanup, we now have this:

shell$ ./drizzled/drizzled --datadir=/home/eday/other/drizzle.data
InnoDB: The InnoDB memory heap is disabled
InnoDB: Mutexes and rw_locks use GCC atomic builtins.
090827  0:29:34  InnoDB: highest supported file format is Barracuda.
090827  0:29:34 InnoDB Plugin 1.0.3 started; log sequence number 8157346
Listening on :::4427
Listening on 0.0.0.0:4427 …

Folks, I just want to warn you how buggy partitioned tables with negative values are. Never use negative values for InnoDB auto_increment columns!!!!

• Assertion failed: next_insert_id >= auto_inc_interval_for_cur_row.minimum()
• partitioned innodb tables end up with duplicate primary key values!
• AUTO_INCREMENT errors with partitioned InnoDB tables in 5.1.31
• Assertion failure in file …