[Tickets #11590] Re: Kolab backend: IMAP cache does not get updated

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Ticket URL: http://bugs.horde.org/ticket/11590
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  Ticket             | 11590
  Updated By         | Jan Schneider <jan at horde.org>
  Summary            | Kolab backend: IMAP cache does not get updated
  Queue              | Horde Framework Packages
  Version            | Git master
  Type               | Bug
  State              | Assigned
  Priority           | 3. High
  Milestone          |
  Patch              |
  Owners             | Gunnar Wrobel
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Jan Schneider <jan at horde.org> (2012-10-31 20:03) wrote:

> This is currently the expected behavior as the implemented  
> synchronization strategy is pretty dumb. The old code had no  
> synchronization strategy and so it always synchronized the data on  
> access. You should be able to go back to the old behavior by  
> modifying Horde/Kolab/Storage/Synchronization.php. Add a "if (false  
> && ..." to both conditionals present in that file. Does that revert  
> back to the expected behavior?
>
> I lack a final plan concerning the synchronization strategy. The  
> problem with the synchronization is that each list synchronization  
> costs two IMAP calls (LIST and METADATA) and each data  
> synchronization as well (STATUS and SEARCH - the latter identifies  
> deleted messages).
>
> Doing this type of synchronization with each and every data access  
> keeps the data in sync always. But of course it is a performance  
> drag. Especially if you build the calendar and have access to ten or  
> twenty different folders. And most of the times this type of  
> synchronization is not really necessary. What describe - concurrent  
> access with two clients to the same folder - is not the default case  
> after all. At least not for personal folders.
>
> At some point I wanted to create the "kolab" Horde application to  
> offer at least a "Sync now" button to provide the user with control  
> over the synchronization strategy. This would put the user into  
> control of the synchronization strategy, would avoid performance  
> issues but would not be an improvement of usability. Probably there  
> are better solutions.
>
> Any suggestions?

At least when using Horde_Imap_Client we can leverage from the IMAP  
server's feedback whether the cache needs updating.