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rubymemorymemory-leaksmechanizemechanize-ruby

Mechanize memory leak despite setting history size to 0 and clearing history

Here is an example script that reproduces the issue

require 'mechanize'

agent = Mechanize.new
agent.history.max_size = 0 

5000.times do |i| 
  agent.get('http://www.yahoo.com')
  agent.history.clear

  p `ps -o rss -p #{$$}`.strip.split.last.to_i * 1024 # Prints out memory usage of the ruby process
end

I'm doing both agent.history.max_size and agent.history.clear but it seems that memory usage is increasing with each loop.

Here is the output showing increasing memory usage (starts at 48MB and increases by 1-2MB with every loop).

48603136
50274304
51470336
53260288
54984704
55836672
56799232
57884672
59150336
60358656
61349888
62193664
...

How do I get Mechanize to stop leaking memory?

Solution

  • That's not a memory leak, some things just haven't been gc'ed yet. Put:

    GC.start

    in the loop if you feel like you need it, otherwise it's probably safe to ignore.