Re: Fetching headers takes long?

[Simon Josefsson <jas@pdc.kth.se>]

Kai.Grossjohann@CS.Uni-Dortmund.DE writes:

> I recently converted from nnml to nnimap and I now see that fetching
> headers for a group takes quite some time, even if I do `2 2 =',
> say.

Header fetching does take some time. Gnus was designed around NNTP
(NOV) headers, and nnimap need to convert it's data into that format
which take some time.

> I have set gnus-fetch-old-headers to t, btw.

This forces nnimap into fetching all headers in the group, I
think. This is what's causing your performance hit, I'd say.

Nnimap could have a .overview file just like nnml and only request
headers from the server when there wasn't a entry in the .overview
file. This would be neat, and make things almost as fast as nnml. I've
partly implemented this so perhaps I should wrap it up.

OTOH you can use the Agent which uses nnml and things should be much
faster. OTTH Agent integration with nnimap is not finished,
moving/copying articles around in disconnected mode is not supported,
for example.

> If it is normal behavior, is it possible to make it faster or is
> this a limitation of the IMAP protocol?

There's no problem in the protocol, header fetches are fast.