Hi all,

Here is another installment on working in the cloud, the AWS cloud that is. Today's topic: creating a custom AMI. This may sound like as easy task. And it would have been, had AWS documentation been up to scratch. I spent lots of time messing around with this, and I finally got it to work. Here's how:

1. Launch an exiting image (I chose a Fedora 8 image). Modify the /var/www/html/index.html file to something else (thus making it "your unique AMI). I went one step further: I installed JDK 6 and MySQL on mi AMI for use at a later date.
2. Now you have to upload your private key and x509 certificate to the AMI. Here's how to do this in the terminal:

       scp -i ~/.ssh/<yourkeypair.pem> ~/.ec2/<pk-whatever.pem> ~/.ec2/<cert-whatever.pem> root@your-public-DNS:/mnt.

   The private key and x-509 certificate should be uploaded to the mnt directory to prevent them from being …

An example of a basic MSSQL (Microsoft SQL Server/SQL Server Express) query using PHP.

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$szQry = "SELECT column1, column2 FROM foo";
$szDBConn = mssql_connect("host","username","password");
mssql_select_db("database_name", $szDBConn);
$saResults = mssql_query($szQry, $szDBConn);
while($obResults = mssql_fetch_row($saResults))
{
   echo $obResults[0]." ".$obResults[1];
}
mssql_close($szDBConn);

Comments/description of Example

Line #1

SQL statement that will be sent to the MySQL database server.

Line #2

MSSQL database login credentilas; host (127.0.0.1), username and password.

The “host” is the server name or IP address of your database server. If your host has multiple instances the “host” value would be formatted like so …

This Thursday (March 19th, 14:00 UTC), Susanne Ebrecht will give a MySQL University session on How to Use Charsets and Collations Properly. Susanne works at the MySQL Support team and is an expert in character set issues.

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). …

This video has been going around for some time now, but I think its worth the post for those that have yet to see it.

Video Source: The Web Site is Down

It’s been a few months since we‘ve started actively using ActiveMQ queue server in our project. For some time we had pretty weird problems with it and even started thinking about switching to something else or even writing our own queue server which would comply with our requirements. The most annoying problem was the following: some time after activemq restart everything worked really well and then activemq started lagging, queue started growing and all producer processes were stalling on push() operations. We rewrote our producers from Ruby to JRuby, then to Java and still – after some time everything was in a bad shape until we restarted the queue server.

So, long story short, after a lots of docs and source code reading we’ve found really interesting thing. There is a “feature” added in the recent ActiveMQ release …

Here is my experience trying to run OpenBSD with XenServer 5 Enterprise.

• XenServer console doesn’t function properly as it keeps overlaying text displayed previously or anything you have typed into the console. Makes it very difficult to read and see what you are doing. As well it appears numerpad with numlock on does not work either. The best work around is to SSH into OpenBSD.
• Receiving the following error messages at boot up, “clock: unknown CMOS layout” and “rl0: watchdog timeout”. Yes the NIC is being detected as a Realteak 8139. If I check /var/run/dmesg.boot out of the two error messages I only see the “clock: unknown CMOS layout”. So I would assume the watchdog timeout message occurs after initial boot sequence.
…

How would one concatenate strings from a column (multiple rows) into a single row using MySQL? I see its possible with MS SQL Server 2005 and above. Any incite into how to achieve this in MySQL would be much appreciated.

MS SQL Server 2005 - Example

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SELECT Web_Account_ID,
GroupNameConcat = REPLACE(
        (
        SELECT
                Web_Account_Group_Name_ID AS [DATA()]
        FROM
                tblWebAccountGroup WAG
        WHERE
                WAG.Web_Account_ID = WA.Web_Account_ID
        ORDER BY
                Web_Account_Group_Name_ID
            FOR XML PATH ('')
        ), ' ', ',')
FROM tblWebAccounts WA
ORDER BY Web_Account_ID

Query Results Example

Source: …

Wouldn't it be cool to enhance MySQL creation table syntax to do this?

CREATE TABLE t1 (
  my_date DATE,
  my_month VIRTUAL INT AS (DATE_FORMAT(d,'%Y%m'))
);

And later, when you insert '2008-08-23' in my_date, then automatically my_month will be set to 200808.
Yes, it would be cool, and it has been done. Andrey Zhakov, a so far unknown to me community contributor, has extended the server code to implement virtual columns (WL#411) and functional indexes (WL#1075)
Andrey has published …

I want to get opinions from outside of my daily circle of people on the best server hardware to use for MySQL. I remember from the conference somebody (Pipes?) mentioning a particular Dell server with multiple disk RAID10 that could supposedly be had for about $6k but I completely misplaced the model number (Frank, did you get my email?).

I know that a multi-disk RAID array with a bunch of fast disks (15k RPM?) is probably the most important method of improving performance, followed by the amount of RAM, so I'm trying to find the best combination/balance of the two. However, server prices on the Internet range so much that I don't even know where to begin to tell a good deal from a bad one. I don't think SSDs can play a role here, because we …