Re: Speed difference in Gnus: a step in the right direction
"Stephen J. Turnbull" <stephen(a)xemacs.org> writes:
Hrvoje> The way I understand it, nnml is supposed to be the
Hrvoje> "fast" one. Reading the headers is fairly slow, but its
Hrvoje> speed has never been O(n^2).
My reading of the manual is that it's a tradeoff between entering
the group (nnml slow, nnfolder fast) and working with individual
messages (nnml fast, nnfolder slow).
I seem to understand the opposite. nnml is fast on entry because of
the overview index, and slow when working with individual messages
because it works with a bunch of small files (nnfolder uses an
in-memory buffer, presumably saved in the end).
For example, from the "Comparing Back Ends" node:
[nnml] maintains a Usenet-style active file [...] and also creates
"overview" files *for efficient group entry* [emphasis mine], as
has been defined for NNTP servers for some years now. It is
slower in mail-splitting, due to the creation of lots of files,
updates to the `nnml' active file, and additions to overview files
on a per-message basis, but it is extremely fast on access because
of what amounts to the indexing support provided by the active
file and overviews.