How to find and fix a Rails and Couchbase memory leak

Question

I have the following test code:

def loop_bucket_gets
    bucket = Couchbase::Bucket.new({:node_list => ['xxx.xxx.xxx.xxx:8091', 'yyy.yyy.yyy.yyy:8091'],
                                    :bucket => 'Foo',
                                    :pool => 'default',
                                    :expires_in => 1.day,
                                    :default_format => :marshal,
                                    :key_prefix => '_foo'
                                   })

    i = 0
    loop do
      begin
        i += 1
        bucket.get "ABC#{i}"
      rescue ::Couchbase::Error::Base => e
        nil
      end
    end
  end

When I execute this in the Rails console the memory leaks.

I'm using:

couchbase 1.3.10 gem
libcouchbase 2.4.3

I created an issue at https://www.couchbase.com/issues/browse/RCBC-187

@AlejandroBabio This is test code, I use it to confirm that memory keeps growing thus I mustn't stop the loop. — Lazarus Lazaridis, Nov 03 '14 at 11:42
Look here: https://github.com/couchbase/couchbase-ruby-client/blob/324b11ae73934238ab255eaf4f1cd6dab6a239fc/ext/couchbase_ext/get.c#L229 — Dmitry Polushkin, Jul 18 '15 at 22:34
Easy, without any debugger or IDE: https://github.com/couchbase/couchbase-ruby-client/blob/324b11ae73934238ab255eaf4f1cd6dab6a239fc/ext/couchbase_ext/get.c#L251 ctx initialized, used, but haven't cleared after all. — Dmitry Polushkin, Jul 18 '15 at 22:35
@LazarusLazaridis You created a task and reported an issue in Couchbase, and it is currently in RESOLVED state, did you get your answer? — Alireza mohagheghi, Nov 18 '22 at 09:28

score -1 · Answer 1 · answered Feb 27 '23 at 11:03

There is no terminating condition in your loop so it's going to run forever and cause the memory issue you mentioned. You should add a relevant break condition in your loop and test if it resolves the issue.

def loop_bucket_gets
    bucket = Couchbase::Bucket.new({:node_list => ['xxx.xxx.xxx.xxx:8091', 'yyy.yyy.yyy.yyy:8091'],
                                    :bucket => 'Foo',
                                    :pool => 'default',
                                    :expires_in => 1.day,
                                    :default_format => :marshal,
                                    :key_prefix => '_foo'
                                   })

    i = 0
    loop do
      begin
        i += 1
        bucket.get "ABC#{i}"
        break if YOUR_TERMINATING_CONDITION
      rescue ::Couchbase::Error::Base => e
        nil
      end
    end
  end

How to find and fix a Rails and Couchbase memory leak

1 Answers1