Comparing mail backends

[Kai.Grossjohann@CS.Uni-Dortmund.DE (Kai Großjohann)]

Each kind of mail backend has its own advantages and disadvantages.
Here, I'd like to learn something about speed.

Which operations are particularly slow and which operations are
particularly fast for the following backends?

  - nnmbox
  - nnbabyl
  - nnfolder
  - nnmh
  - nnml

Operations I'm thinking of:

  - Mail splitting.
  - `B c' and `B m' within a server.
  - Entering a group (ie, fetching headers).
  - Searching in a group with `M-s'.
  - Checking all groups when Gnus is started.  (I'm not sure what
    happens here, but I think at least the number of unread messages
    in each group needs to be computed.)

Feel free to add operations which I haven't thought of.

Of the above, I know nnml best, and I have seen a bit of nnfolder and
nnmh.  But I don't know how nnfolder and nnml compare when moving
messages between groups -- which one is faster?  I think fetching
headers is fastest in nnml, then comes nnfolder, and then nnmh.  Is
this correct?  nnmh seems to be very slow when Gnus is started, at
least compared with nnml; but how does nnfolder come in?

And I have no idea whatsoever about nnmbox and nnbabyl.

kai
-- 
I like BOTH kinds of music.