[Tickets #12339] Re: PING-SYNC storm in ActiveSync is back

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Ticket URL: http://bugs.horde.org/ticket/12339
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  Ticket             | 12339
  Updated By         | Michael Rubinsky <mrubinsk at horde.org>
  Summary            | PING-SYNC storm in ActiveSync is back
  Queue              | Synchronization
  Version            | Git master
  Type               | Bug
  State              | Feedback
  Priority           | 2. Medium
  Milestone          |
  Patch              |
  Owners             | Michael Rubinsky
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Michael Rubinsky <mrubinsk at horde.org> (2013-06-14 00:24) wrote:


> Attached.maybe the following is the report of the problem?
>
> ERR: Unknown message.

Bug: 12316

> Now that I've enabled per-device sync logging, I can see something  
> else. My Android is blocking on this error (I guess),

This is happening because, for some reason you are getting UIDs back  
from your IMAP server that are lower than the minimum UID received in  
the initial sync. No idea why this is happening at this point. My  
guess is that the UIDs are no longer valid (UIDVALIDITY changed), but  
I'm waiting for someone to test those changes.

> but the traffic storm I'm seeing is actually from my Outlook 2013 -  
> it's log file is huge and growing by megabytes per minute (60,100  
> lines per minute). However, email seems to be in sync - it's simply  
> continually checking?

Yes, that's how ActiveSync works. The difference with Outlook is that  
it syncs EVERY email folder COMPLETELY and pushes every folder,  
whereas android, by default, only pushes INBOX. Now, if it's actually  
issuing continuous SYNC requests (and not looping within the single  
SYNC request) then *that* is a problem.

> I have set "forcedheartbeat" in an attempt to slow down Outlook -  
> but even after a restart doesn't seem to have any effect

This setting is simply the time that each PING or SYNC request lasts  
before initiating another one, so you will still see the checks. If  
you want to reduce the number of actual checks performed during each  
heartbeat you should increase the 'waitinterval' setting. This will  
cause the server to wait longer between backend checks. Of course,  
this also means it will be longer before the change is detected and  
therefore longer to be pushed to the device.

> I'm guessing there's a corrupt email that causes Android to fault and stop,

Not a corrupt email, but unexpected (or unexplained) email UIDs being  
received from the imap client.

> whereas Outlook gets past it but then goes back to re-check and ends  
> up looping?

No idea how Outllook is getting past this. A log from Outlook would  
possibly be helpful as well.