Thank you all for your replies
Regarding the IMAP server side suggestions, the thing is that my old
webmail (Horde 3.0.10+IMP 4.0.4) is connecting to the same IMAP server,
and it has no problems dealing with large inboxes -1 or 2 seconds max.
for displaying inboxes with more than 40000 mails never been cached-, so
my question remains: has the imp code changed in a way that would
explain that behaviour? For example, when I click in the Date tab to
reorder my messages, my old webmail only reorders the ones that are
visible, while the new one goes to the first (or last) page instead.
This suggests that the old one is only dealing with the ones that are
visible, but I can't be sure. The settings are the same in both webmails
as far as I can see.
Thanks again for your help.
Jose Manuel
On 11/03/2010 07:12 PM, Michael M Slusarz wrote:
Quoting Aria Bamdad <[email protected]>:
I have the same problem with my setup. I use an IBM IMAP server and
after
running several traces, we found that IMP tends to request specific
detailed
information about every mail item in the inbox at logon. When you have
1000's of messages and if your IMAP server is not local or is not super
fast, this results in the slow login problem reported here. My
solution to
this was to set the $conf[server][sort_limit] variable (IMP
configuration,
Server tab) to a small number and basically turn off sorting if there
are
too many messages in a mailbox. Doing this, resulted in eliminating
the
massive request at login.
The bottleneck here is your IMAP server then, not IMP. RFC 3501 is
unfortunately limited in that it does not allow server side sorting
for anything other than arrival time. So to perform sorting on ANY
other field requires the IMAP client to download all of the necessary
headers from EVERY message in the mailbox to do the sorting on the
client-side. For a disconnected client, this is a potentially brutal
operation (it is especially brutal for threaded sort, since it relies
on several messages headers at once). IMP mediates this by being able
to cache header data, but you have to enable caching.
This is not a problem with IMP because EVERY client has to do this.
You won't see this in desktop clients, however, since they can do
things like download message headers in the background and cache these
headers. It is difficult, if not impossible, to do this for a webmail
client, however.
Exacerbating the problem is that IMP uses the c-client library to
interact with the IMAP server. Unfortunately, the c-client library is
known to be HORRIBLY inefficient when it comes to querying the IMAP
server. To view a single header (say, for example, the "from" header)
c-client downloads the entire message envelope of every message in the
mailbox, rather than just the header requested. There is *nothing* we
can do about this in IMP 4 since we don't control the IMAP commands
being sent to the server.
So now the good news. First, many modern IMAP servers now support
server-side sorting and threading (RFC 5256 - only formally adopted in
June 2008). This eliminates issues related to sorting delays. Better
yet, many of these IMAP servers cache the header information
internally so they don't have to parse all mail messages in the
mailbox every time a sort request happens. This drastically speeds up
mailbox accesses.
Additionally, c-client is no longer an issue in IMP 5 since we have
replaced the c-client library with a native Horde IMAP library that is
magnitudes faster.
What would be nice is if IMP only requested specifics about messages
that
appear in the current window rather than ask for every message in the
mailbox. The problem is that if a user selects any sort field other
than by
arrival order, then at login, IMP asks for detailed information about
every
mail item in the mailbox, slowing down login to a crawl.
This is (unfortunately) correct behavior. You can't sort a single
"message view". To sort a mailbox requires processing *every* message
in the mailbox - or else how would you determine what messages a view
entails? We can work around this a bit - namely, once we get a sorted
list for a mailbox, we can continue to use this sort until the mailbox
structure changes. But that only provides partial relief. The only
way to truly remedy this situation is to use an IMAP server that
supports RFC 5256.
michael
--
Jose Manuel Blanco Ramos
European Space Astronomy Centre (ESAC)
European Space Agency (ESA)
E-mail: [email protected]
Tel: +34 91 8131 185, Fax: +34 91 8131 322
P.0. Box 78, 28691 VILLANUEVA DE LA CAÑADA
SPAIN
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