[horde] Horde performance with ActiveSync?

[Sebastian Arcus]

On 10/04/18 21:10, Michael J Rubinsky wrote:
> 
> Quoting Sebastian Arcus <s.arcus at open-t.co.uk>:
> 
>> On 10/04/18 18:05, Michael J Rubinsky wrote:
>>>
>>> Quoting Sebastian Arcus <s.arcus at open-t.co.uk>:
>>>
>>>> On 10/04/18 15:41, Arjen de Korte wrote:
>>>>> Citeren Sebastian Arcus <s.arcus at open-t.co.uk>:
>>>>>
>>>>>> I have a Horde 5.2.17 + PHP 5.6.35 + Postgresql 9.2 + Lighttpd 
>>>>>> 1.4.49 with 10 iPhones/iPads in ActiveSync/Exchange mode. The 
>>>>>> users have fairly large Inboxes - some of them of 20 000+ emails. 
>>>>>> On IMAP that is not causing any issues, and hardly any load on the 
>>>>>> server.
>>>>>
>>>>> Which IMAP server do you use? Is it local to the webserver?
>>>>
>>>> Thank you for replying. I use Dovecot which runs on the same server 
>>>> as Horde.
>>>
>>>
>>> Assuming the load you are seeing is still present after the devices' 
>>> initial sync,
>>
>> Come to think of it, because after the initial setup all devices have 
>> to re-download all headers, there is a good possibility that 2-3 of 
>> them are still in the process of pulling down all their headers (one 
>> of them has 80 000 just in the Inbox). I take it downloading headers 
>> can be expected to generate a significant load? On imap/Dovecot, the 
>> load was always negligible, but I suppose ActiveSync+PHP/Horde is a 
>> completely different kind of beast.
> 
> Well, it would be very unusual for the EAS client to download ALL of the 
> available email headers. Normally you would limit this to a specific 
> time frame like the last 2 weeks or so. The Horde server takes care of 
> expiring and refreshing the email on the client that falls within the 
> requested time range. Older email would still be available via searching.

I looked into this, but the highest limit iOS is offering (aside from 
"No limit") is 1 month. Which is really not enough for the usage type on 
this site. If they had 6 months or 1 year as options, that would have 
been much more useful.

However, I didn't know that you can search through emails which are not 
visible or downloaded - that is definitely a useful bit of info - thank you!

> 
> Even then, it normally only downloads the INBOX by default (unless the 
> user explicitly sets other folders as "pushed").

I think that as soon as you try to access another folder, it tries to 
download its contents. And as part of testing during configuration, to 
make sure it is all working fine, I would go in-and-out of "Sent" and 
various other email folders on the iOS devices.

> 
> If they really are, indeed, asking to sync the ENTIRE 80k+ messages in 
> the INBOX, that will certainly take a bit of time, and I wouldn't doubt 
> that the client might run into performance issues with that number of 
> messages though I admittedly have no experience with that kind of 
> message count on an iOS device.

On IMAP (which is what we used to use here until now), iOS clients have 
been coping ok for the last 8 years downloading the entire list of 
messages. I have to say, even I had doubts that iOS devices could cope 
with 80 000 messages in an Inbox - but to my surprise it has been 
working fine and I had no complaints from users.

Thanks again for the hints!