For this performance test I have made a copy of a quite big object from one of our production apps. If this object is converted plain to YAML it takes about of 3.7 MB, and in byte stream ruby marshalling about 1.8 MB. It consists mainly of big hashes, whereas the hashes hold strings as keys and integers as values. Summed all values together in that object that might be around 200k objects (basically short strings and DWORD integers)

Using ruby 1.8.7 converting that object to YAML is quite a pain. Not using only over 200 MB of RAM after calling the .to_yaml method but also taking 25.6 seconds to fullfill that request on a small Debian 6 system.

The .to_json performs an edge faster with 3.8 seconds and using only about ~ 30 MB of RAM usage for the ruby process.

Much better performance showed the built-in marshalling method. The ruby built-in Marshal.dump resp. Marshal.load methods did not show a significant difference. Dumping and loading take each approximately 90 ms.

Finally retrieving that object from memcached, whose sub objects are kept in 5 chunks to not excess the 1 MB limit takes about 40 ms. And in this time not only the bytestream is being converted to an object, but also the whole data is transmitted via TCP sockets.

*excessive RAM usage when streaming to YAML.

Finally I hope there is going to be some major improvements to the built-in JSON and YAML performance to come with future ruby and rails versions. Enough yaml libraries out there ...

Internet Explorer 7 had after several years of waiting PNG's with alpha channel supported. Internet Explorer 9, which is now out for beta comes with rounded corners (CSS3 border-radius), currently passes 95% of the ACID3-Test and utilizes Direct2D which gives very smooth browsing experience on websites were you zoom and drag a lot like bing maps or google maps.

Interestingly due to the new Direct2D implementation, google maps is even faster in IE 9 as in Google's Chrome 5 itself, which is still my favourite browser - but at least microsoft did a big step towards the future. Let's hope that the little style bugs disappear before the final release.

Links

• Internet Explorer 9 beta Download
• ACID 3 Test
• Direct2D Wiki Page
• Bing Maps
• Google Maps
• 54 amazing websites to try in IE 9

Till 2011 our new CMS will be exclusively available for asiacomfort.com and is being developed steadily.

1. Ruby on Rails - the agile and fast web framework
2. memcached - unix native, distributed, high performance, memory object caching system
3. CouchDB - document oriented, distributed and scalable database system beyond SQL
4. jQuery - the all in one javascript and ajax framework

Another approach often recommended is to use FasterCSV to build the csv-file. FasterCSV is a nice tool when you want to freely create custom csv files, but performance wise this approach takes some time if you are really exporting large tables (>10000 rows).

Much faster is to just use MySQL's built-in method for exporting a table directly into csv format.

Just put this into the model you want to export as csv.

# model # function returns table as csv string def self.to_csv db_name = self.configurations[Rails.env]['database'] # pay attention to the backticks `` return `echo "use #{db_name}; select * from #{self.table_name};" | mysql -u monitor_user --password="1234"` end

Ensure that you have a seperate mysql user with only select priviliges on your database to get this working safely - in this example the user name is 'monitor_user' with password '1234'.
Of course if you are planning to implement this functionality in several models, you could put this into a module into ./lib and just include the module in each desired model class.

To provide the generated csv string from the model for download, you could use some code like this in your controller.

# controller def download_csv send_data(MyModel.to_csv, { :type => 'text/csv', :filename => "my_model_#{Date.today.to_s}.csv" } ) end

Beneficial over the phpmyadmin solution,
you define the security rules directly in your application,
no need to rely on mysql priviliges and
most important, you don't expose a common interface to the database server which is permanently under fire from automated attack bots¹.

1. for those of you don't know about phpmyadmin ... even we don't have it running on our server - we have more than 1000 requests per month on a farely unpublic domain, trying to gain access to several possible phpmyadmin paths and underlying scripts - so its probably better to turn the doorbell of on permanent knock-a-door-runs

Samsung, Eizo, Dell

I ordered a Samsung SyncMaster 2243BW, as this display was one of the lowest priced models for around EUR 180 with 22 inch and pivot stand. Shortly after the arrival and setup of the display I noticed that these so popular TN-Panels had much worse viewing angle properties than I was expecting. Of course I knew about the properties of TN panels, that's why I was buying the Eizo 2 years ago having a S-PVA panel, offering the best color reproduction, highest font detail, constant color and contrast over the full viewing angle compared to any other LCD technology. My disappointment over the extraordinary nasty color shifts occurring on little viewing angle changes leaded me to the decision to get another display for comparison. I have heard IPS technology made some advantages in the past, and as you can get displays with this type of panel for little extra money compared to TN panels I decided to give them a try. The second display I ordered was a Dell 2209WA having an E-IPS panel as this was nearly the lowest price 22 inch model with pivot stand and E-IPS panel for around EUR 250.

Comparison

On the following figure you can see the difference in color and contrast reproduction on a tilted viewing angle. On the left, the Samsung, its fairly recognizable that light tones are shifted dramatically to green, red, grey, and even white is shifted to blue, wheres blue is shifted to green. And the more darker mid-tones become very vibrant, loosing a lot of tonal detail. Depending on the viewing angle this changes all the time. So if you are looking for wicked spectral effects this display might be interesting for you, although I prefer the reproduction quality can be seen on the second photograph - the IPS panel of the Dell display reveals nearly no color shifts even on highly tilted viewing angles. One downside even for Dells IPS' - the black parts get clearly brighter on larger angles, but this effect is at least in daylight situation negligible.

Both shots are taken and processed with totally equal settings.

If you are used to simple naming conventions from rails you expect to have the login in my case on http://blog.hyperco.de/login - but the wordpress login page sits in wp-login.php - that seems to be a general design rule. All of the pages in the wordpress root start with 'wp-' and end with '.php' - not my prefered taste.

So I thought, wouldn't it be nice to have apache redirect all requests to files not found on the disk to the wordpress style named files?

I assume you are using apache web server and you have the RewriteEngine aka mod_rewrite enabled, then this will do the trick:

RewriteEngine on RewriteCond %{LA-U:REQUEST_FILENAME} !-f RewriteCond %{LA-U:REQUEST_FILENAME} !-d RewriteCond %{REQUEST_URI} !^(.*)\.php$ RewriteRule ^/(.*)$ /wp-$1.php [R=307]

This peace of code you can easily be pasted into your vhost config or .htaccess file or whatever else config file you are using.

Explanation

1. in line one we enable the RewriteEngine
2. apply rule only if no file on disk with this name exists
3. apply rule only if no directory on disk with this name exists
4. apply rule only if REQUEST_URI does NOT end on .php
5. rewrite (redirect) /login to /wp-login.php

<% if c = @customer[:image] %>; <img src='...' />; <% end %>

but obviously this code would look much more nice with short tags enabled, so I could use code like

% if c = @customer[:image] <img src='...' /> % end

but poorely, in a standard rails env this trim mode for ERb is not enabled by default.

For Rails 2.1.2, I've made it working by

# environment.rb: # ALLOW open ruby code lines inside templates ActionView::Base.erb_trim_mode = '-%'

At least for Rails 2.3.4 this does not works as a class is frozen error is raised. I'll post an update here, when I found out a simple solution to get this working in rails 2.3.x without the need to install the trim mode plugin.