These are:

• Logging to DB instead of log files
• Runtime configuration of logging.

Logging to DB instead of log files

Coming from a web development background rather than a sysadmin background I'm far more comfortable manipulating and analysing data using SQL. So to be able to log all the queries or just the slow queries for an application to the db during application development or load testing is a huge benefit.

To enable logging to DB you can add the following to your my.cnf

The logs will be written to the 'slow_log' and 'general_log' tables in the mysql database.

Note - logging to tables has more overhead than logging to file, so would suggest using it primarily for development purposes.

Full details of the options are on the mysql manual on log tables

Runtime configuration of logging.

This allows you to turn on and off logging without restarting MySQL - which just saves a little bit of time and makes it much nicer for debugging problems.

To turn on the logging of all queries run:

And to turn them both off use:

If you also want to see queries not using indexes in the slow query log you can set the following variable:

Hope it helps, Mark

To do this I used a SSH sock proxy like I have previously blogged about.

So I fired this up so that I could review the site I wanted to look at. It worked a charm through firefox but there is no where to set up the proxy in jmeter.

To make it work you need to let the JVM know what proxy to use like so:

No jmeter will use the socks proxy on port 8080 on my local machine. Nice.

I've just received a copy of the Tomcat 6 Developer's Guide from packt publishing to review.

It's nice timing as I've been working with Tomcat 6 a bit lately and in the new year plan to move some of our production systems over to running Railo on top of Tomcat.

After the extremely busy year Learnosity has had I'm looking forward to reading a few books over the break and coming back in the New Year with lots more ideas and technology to implement.

About Learnosity

Our service:

• Makes it practical for students to practice Oral and Aural skills
• Is efficient and effective for teachers, as they can listen to each student individually at a time to suit them
• Can be used for homework assignments or “High Stakes Assessments”

We are continuing to grow our core development team and we need another great developer to help us keep up with demand.

We need someone who can:

• Use Javascript or Actionscript to create great user interfaces
• Develop highly scalable web applications
• Cut code with the best in the world

You will also need to be:

• energetic with a butt kicking attitude
• ready to create cutting edge web 2.0 apps
• keen to continue learning new technologies
• able to have a conversation with non technical people

You'll need:

• 3 or more years of programming experience
• Expert in at least on Client side language (Actionscript or AJAX)
• Expert in at least one Server side language (eg PHP, Java, ColdFusion, etc)
• Understanding of Object Oriented design
• Understanding of XHTML and CSS

It would be good if you have:

• A degree in Computer Science, Engineering or similar.
• been working with open source tools
• been playing around with iPhone/Android applications
• experience with some of Linux/VOIP/SIP/Asterisk/Jabber/XMPP

This is a full time role and you will be working in a casual workplace with flexible hours in the Sydney CBD.

If this sounds like the job for you, email a covering letter explaining why you'll be great and your resume to mark@learnosity.com - no agencies please.

Seem to be on a roll with Sox tonight. Also figured out how to normalise audio files nicely.

The first thing to do with sox is to get it to calculate the max volume adjustment possible:

This will return a number like: 4.234

You can then call sox again using this number:

And if you're feeling particularly good you can put the whole command on a single line as follows:

Easy when you know how.

However, this time I finally managed to get past all the hurdles and jump through all the hoops to make this work.

Scenario is a follows. Audio file is comes in in alaw or ulaw format and we want to trim any silence before and after it.

First step is to convert it from alaw to pcm encoded wav file as SOX has issues filtering silence in alaw files

Then we do the trimming in one fell swoop.

A huge thanks to this article for giving such a thorough overview of the how silence detection works in sox.

Too easy, when you know how :-)

All the DB storage and application was using UTF8 throughout, but the PDF exports were showing nothing when they should have been showing Chinese characters.

To fix this up you need to do the following:

1. Need fonts installed on system:

2. Need fonts installed in CFAdmin

• Go to CFAdmin and Font Management
• Select directory /usr/share/fonts/truetype/arphic
• Select "Add" and you should see 2 new fonts added.

3: CFdocument Hotfix for CF7.0.2

Configure cffont.properties file

The cffont.properties file is located in /opt/jrun4/servers/{instance name}/cfusion.ear/cfusion.war/WEB-INF/cfusion/lib on the jrun multiserver version.

5. Restart CF

Once you restart CF you documents should be coming out with their Chinese fonts intact.

I'm sure there are additional fonts to add to get it working natively with all the other asian languages, so I'll add to this as and when I need/discover them. Please feel free to post a comment if you find any more font's that should be added to the list.

• Automatically fixing file system errors
• Ignoring directories from updatedb

Automatically fixing file system errors

If you have a remote server, i.e. at a data center 10km or 1000km away this should prevent some panic when rebooting the server remotely.

Ext2/3 will do a filesystem check after a certain number of reboots or time. Most of the time any errors are fixed automatically, but certain errors by default require the root shell and the administrator to fix them. I've seen a few of these happen, but I have always replied yes to the prompts as I don't know enough about file systems to fix it I said no.

So, to prevent the need to rush to a data center and plug in a keyboard and mouse just to press the "Y" key there is and option to automatically assume yes.

On Ubuntu in the file /etc/default/rcS you need to change the following:

Ignoring directories from updatedb

To tell locate to ignore a directory you need to add it to the PRUNEPATHS line in the /etc/updatedb.conf file like so:

In the above code I have added the /srv entry to make it ignore all my backups which are held under the /srv directory.

Note: These tips were tested on Ubuntu linux, other distributions will have similar functionality but the file locations may vary.

Cheers, Mark

This simple find command shows the offending files:

A quickie but a goodie.

Cheers, Mark

This didn't transpire and so now we use the following technique on apache to map the folder in and then lock it down with apache.

In the vhost section add the following:

Note: it is important that there is no /farcry mapping defined in the CF Administrator or it will override this setting.

What the above does, is to map in the non-web accessible folder, but then locking it down so it cannot be browsed from the web. This seems pointless but CF can still see the files and correctly resolves the paths even though they are secure from the outside world.

This then allows us to version our sites independently - i.e. if we want to upgrade from farcry 5 to 5.1 we can do it one site at a time, instead of having to test them all at once.

Note - Railo already has per vhost mappings which solve the same problem as this. But if you are on CF7 or CF8 then this works a treat.

Cheers, Mark