Re: Maildir backend

[prj@po.cwru.edu (Paul Jarc)]

Matt Armstrong <matt@lickey.com> wrote:
> Have you considered placing NOV data in a single .overview file like
> nnml?

nnmaildir used to do that.

> What is the advantage to keeping nov data in separate files?

Historically, one of the reasons I made that change was so that you
could remove an individual NOV file to force nnmaildir to reparse the
message itself.  You can still do that, but it's no longer necessary.
The message is now automatically reparsed when either it or
nnmail-extra-headers has changed.

More recently, there were some speed changes to nnml, having to do
with having to load and parse the entire .overview file to find just
one line.  nnmaildir punts to the filesystem; the kernel parses the
directory file to find the entry we're looking for.  The kernel has
the ability to organize the directory in such a way that it won't have
to read the whole thing linearly, so there's an opportunity to beat
nnml there.  (It's too bad the opportunity is so often missed.)  nnml
also has the disadvantage of wading through all the information for
all the articles, rather than just identifiers and pointers to the
identified information.  And it's all in text format.

> Neither nnml nor nnmailder are probably the best tool for storing
> HUGE mail folders.

Probably true at least for traditional filesystems.


paul