Question

I have a pretty expensive method in my model that compares text items of arrays for many many items.

It runs really slow. If I use a relational database table and compare the ID’s only, will my method run a lot faster?

/EDIT

I’m attempting to benchmark the below:

 @matches = @location_matches.sort do |l1, l2|
      l1.compute_score(current_user) <=> l2.compute_score(current_user)
    end

    @matches.reverse!

Answer 1

To be short, I guess number comparison will be faster because comparing string is about comparing character after character (advice: in Ruby use symbols when you can, their comparison is much faster).

Whatever, you’ll find there, everything you need to benchmark and get your detailled results.

A code sample:

require 'benchmark'

n = 50000
Benchmark.bm do |x|
  x.report("for:")   { for i in 1..n; a = "1"; end }
  x.report("times:") { n.times do   ; a = "1"; end }
  x.report("upto:")  { 1.upto(n) do ; a = "1"; end }
end

The result:

                user     system      total        real
   for:     1.050000   0.000000   1.050000 (  0.503462)
   times:   1.533333   0.016667   1.550000 (  0.735473)
   upto:    1.500000   0.016667   1.516667 (  0.711239)