[sup-talk] [PATCH] maildir speedups

[Grant Hollingworth]

* William Morgan [2008-05-24 22:34 -0400]:
> Published on 'maildir-speedups' and merged into next. Thanks!

Sup had my CPU working overtime after I updated. I ran ruby-prof and found
that the line

    @ids_to_fns.delete_if { |k, v| !@ids.include?(k) }

in Maildir#scan_mailbox was the culprit.

Those id lists are pretty long and include? means comparing each id (a Bignum)
in @ids_to_fns with every id in @ids.

A faster method is

    @ids_to_fns = @ids.inject({}) do |hash, i|
      hash[i] = @ids_to_fns[i]
      hash
    end

Or (less pretty but faster and probably clearer)

    new_ids_to_fns = {}
    @ids.each {|i| new_ids_to_fns[i] = @ids_to_fns[i] }
    @ids_to_fns = new_ids_to_fns

But I guess the real question is whether the line is even needed. There
probably won't be a big difference between @ids_to_fns.keys and @ids, so why
not leave some extra values in the hash?