[Dovecot] IDLE command timeout

[Chris Wakelin]

Sim Harbert wrote:
> It isn't a matter of the client being broken.  My Treo client properly 
> reconnects when the IDLE command is disconnected due to the timeout, but 
> this means it has to reconnect every 30 minutes.  I want to avoid the 
> overhead of reconnecting all the time and just stay connected.  The 
> reconnections chew up battery life since they involve a lot more 
> wireless network activity than being in IDLE mode.
> 
> The "outlook-idle" workaround doesn't help, since it requires a 
> reconnect with the server.  Well, maybe it wouldn't require a full 
> reconnect, so I suppose it might be a tiny bit better than the actual 
> IDLE disconnect.

It shouldn't cause much traffic, just something like (C:=client, 
S:=server) :-

C: 1234 IDLE
S: + idling

29 minutes later ...

S: * 456 EXISTS
C: DONE
S: 1234 OK Idle completed.
S: * 456 EXPUNGE
C: 1235 IDLE
S: + idling

etc. I can't be bothered to wait 29 minutes for the exact sequence ;) 
but it doesn't involve a reconnect.

> 
> I believe the 'mailbox_idle_check_interval' just gives the minimum time 
> between when the server will notify the client of changes.  If set to 30 
> seconds, that would mean that if mail came 10 seconds apart, then client 
> wouldn't be notified of the second email until 30 seconds after the 
> first.  (This is all just based on the short description in the 
> configuration file...)
> 

Oops, sorry, you're right! The disconnect timeout looks like it's 
hardcoded in src/imap/common.h, at least in dovecot-1.0-stable (it's 
specified in the IMAP RFC, I believe), so you'd need to modify it and 
recompile.

/* Disconnect client after idling this many seconds */
#define CLIENT_IDLE_TIMEOUT (60*30)


> Is there more extensive documentation of the configuration settings 
> somewhere?  The website doesn't document the configuration options.
> 
> -Sim
> 

Not yet, I think. Still, it's a Wiki, so we ought to be able to 
contribute our own!

Best Wishes,
Chris

-- 
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Christopher Wakelin,                           c.d.wakelin at reading.ac.uk
IT Services Centre, The University of Reading,  Tel: +44 (0)118 378 8439
Whiteknights, Reading, RG6 2AF, UK              Fax: +44 (0)118 975 3094