Are you using Dovecot as imap server? Might be the index file(s) get
corrupted.
Alan
On 11/4/2010 4:34 PM, Jose Manuel Blanco wrote:
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
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