ActiveRecord Optimization with Scrooge - igvita.com
The idea behind scrooge is both surprisingly simple and powerful: instead of forcing the developer to manually specify each attribute column, simply observe and record for some period of time all of the attribute accesses and then reuse this knowledge in the future to automatically optimize your subsequent query requests.
Related cards:
ActiveRecord: How to use ActiveRecord standalone within a Ruby script
Re-creating a complex ActiveRecord scenario quickly without setting up a full-blown Rails app can come in handy e.g. when trying to replicate a presumed bug in ActiveRecord with a small script.
# Based on http://www.jonathanleighton.com/artic...
Fix [RubyODBC]Cannot allocate SQLHENV when connecting to MSSQL 2005 with Ruby 1.8.7. on Ubuntu 10.10
I followed this nice guide Connecting to MSSQL with Ruby on Ubuntu - lambie.org until I ran in the following errors:
irb(main):001:0> require "dbi"; ...
Ruby: Using the pry debugger in projects with older Ruby versions
In case you want to use pry with an older version of Ruby, you can try the following configurations.
Ruby 1.8.7
Your pry version must not be greater than 0.9.10.
gem 'pry', '=0.9.10'
gem 'ruby-debug',...
Freeze (vendor, unpack) a single Ruby gem with and without Bundler
When you need to patch an existing gem, one way is to "vendor" the gem by copying it into the vendor/gems directory of your Rails project. You can then make any changes you require and Rails will use the vendored version of the gem after a serve...
Fix Capistrano with RubyGems 1.6
After updating your RubyGems, you will probably not be able to run Capistrano any more, but receive an error similar to this:
can't activate net-ssh (= 2.0.22) for [], already activated net-ssh-2.1.0 for [] (Gem::LoadError)
If you have B...
Rails: When defining scopes with class methods, don't use `self`
Sometimes it is useful to define a named scope by implementing a static method with the scope's name on the scoped class. For instance, when a method should decide which existing scope should be the next link in the scope chain. Take this class fo...
Use DatabaseCleaner with multiple test databases
There is a way to use multiple databases in Rails.
You may have asked yourself how you're able to keep your test databases clean, if you're running multiple databases with ful...
How to use pessimistic row locks with ActiveRecord
When requests arrive at the application servers simultaneously, weird things can happen. Sometimes, this can also happen if a user double-clicks on a button, for example.
This often leads to problems, as two object instances are modified in paral...
Fix "An error occurred while installing debugger-linecache" with Ruby 1.9.3
You're better off using debugger-ruby_core_source:
gem install debugger-ruby_core_source
If you can't do this, try the following.
Here is how to fix the following error when installing the debugger gem fails:
Gem::Instal...