Chances are at some point you’ve wanted to get the values of a single column from ActiveRecord. You might have done something like this:

user_ids = User.find(:all).map(&:id)

That’s great and all, but hopefully somebody points out that you can pass ActiveRecord#find a :select key.

user_ids = User.find(:all, :select => 'id').map(&:id)

Now we’re getting somewhere. On a “wide” table (ie. one with a lot of columns, large columns, or binary types stored separately) this alone can be a huge improvement, as just sending all that data across the wire can really waste time. While ActiveRecord is generally good enough performance wise, sometimes getting a little closer to the metal is appropriate, and in comes find_ids.

user_ids = User.find_ids

Benchmarks

Here’s some benchmarks against a fairly “wide” table with 100 records, 10,000 times for each style:

                              user     system      total        real
find(:all).map           26.460000   3.130000  29.590000 ( 72.656614)
find(:all, :select).map  12.770000   0.560000  13.330000 ( 16.232474)
find_ids                  7.870000   0.340000   8.210000 ( 10.465719)

Examples

But that’s not all, it also natively supports other columns, associations, and named scopes.

emails = User.find_column_values('email')
User.wristbands.find_ids
User.scoped(:order => 'created_at desc').find_ids

Installation

script/plugin install git://github.com/stopdropandrew/find_ids.git

Issues

It currently only works with MySQL, but submissions for other adapters are welcome.

I’m still in the process of learning Git, and while it’s been fairly rough in the beginning, I feel like I’m starting to round the curve of really being productive. While we are still primarily using Subversion at Kongregate, I’ve been trying to use Git whenever possible.

For a side project I’ve been working on, I wanted to have my authoritative Git repo in our colo, behind our VPN, to both speed up deploys and to know that we don’t need to rely on a third party service. But, at the same time, I wanted to be able to use Github’s awesome UI.

hooks/post-receive

There’s not a lot to it, but just set up Github as a remote for your server side repo, then drop this into your hooks/post-receive and be sure to make it executable:

#!/usr/bin/env ruby
STDIN.read.split("\n").each do |line|
   oldrev, newrev, refname = line.split(' ')
   
   if refname.match(/^refs\/heads\/(.*)/)
     branch = $1
   
     `git push origin #{branch}`
   else
     puts "#{refname} was weird, not sure what to do."
   end
end

Nothing too special, but I was pretty happy to get it all working without too much effort.