Ruby Memory Management

Question

I have been using Ruby for a while now and I find, for bigger projects, it can take up a fair amount of memory. What are some best practices for reducing memory usage in Ru

Answer 1

Measure and detect which parts of your code are creating objects that cause memory usage to go up. Improve and modify your code then measure again. Sometimes, you're using gems or libraries that use up a lot of memory and creating a lot of objects as well.

There are many tools out there such as busy-administrator that allow you to check the memory size of objects (including those inside hashes and arrays).

$ gem install busy-administrator

Example # 1: MemorySize.of

require 'busy-administrator'

data = BusyAdministrator::ExampleGenerator.generate_string_with_specified_memory_size(10.mebibytes)

puts BusyAdministrator::MemorySize.of(data)
# => 10 MiB

Example # 2: MemoryUtils.profile

Code

require 'busy-administrator'

results = BusyAdministrator::MemoryUtils.profile(gc_enabled: false) do |analyzer|
  BusyAdministrator::ExampleGenerator.generate_string_with_specified_memory_size(10.mebibytes)
end  

BusyAdministrator::Display.debug(results)

Output:

{
    memory_usage:
        {
            before: 12 MiB
            after: 22 MiB
            diff: 10 MiB
        }
    total_time: 0.406452
    gc:
        {
            count: 0
            enabled: false
        }
    specific:
        {
        }
    object_count: 151
    general:
        {
            String: 10 MiB
            Hash: 8 KiB
            BusyAdministrator::MemorySize: 0 Bytes
            Process::Status: 0 Bytes
            IO: 432 Bytes
            Array: 326 KiB
            Proc: 72 Bytes
            RubyVM::Env: 96 Bytes
            Time: 176 Bytes
            Enumerator: 80 Bytes
        }
}

You can also try ruby-prof and memory_profiler. It is better if you test and experiment different versions of your code so you can measure the memory usage and performance of each version. This will allow you to check if your optimization really worked or not. You usually use these tools in development / testing mode and turn them off in production.