[Kolab-devel] [issue3423] [horde] Sync Speed Issue with large number of items

[Tom Malone]

New submission from Tom Malone <tmalone at lancer-ins.com>:

We have recently changed our carrier for our Blackberries and as a result we
have run into an interesting issue.

When trying to do a refresh sync on the contacts for a user we were getting
almost constant time outs.  However, other users were not getting time outs when
trying to do a refresh of their contacts.

It turns out the the user who was having the problems had 2030 contacts while
the other users had 500 contacts.  

The sequence of events that leads to the failure is as follows:

1. The client makes a request to the server for a refresh sync.
2. The Horde reads its history database for all the entries to add and begins
   to build the response packet.  I assume that it also contacts cyrus for the
   actual data.
3. While the Horde is working the network gateway/proxy for the Blackberry
   times out and shuts down the connection for the client.

Since the gateway has already timed out the connection the client fails and the
sync process ends.

This only seems to happen on a large number of items.  If the number is small 
enough the Horde is able to get the response sent out to the client quick enough
and the sync proceeds.

I was able to monkey with the sync packet size in Sync.php to make the Horde
send its response to the client quicker.  This allowed the 2000 contacts to make
it to the client.  However, I'm sure that the issue will crop up again when
someone goes to a larger number of items.

I was wondering if there was a more elegant way of accomplishing this.  Is there
some way to split things up so that the Horde does not need to read all 2000
contacts at once?

If it could do something like read 100 contacts, build and send the packet, and
then read another 100 contacts it might speed up the whole process and avoid the
timeout issue.

Thanks for listening.
Tom

----------
messages: 18664
nosy: tmalone
priority: wish
status: unread
title: [horde] Sync Speed Issue with large number of items
___________________________________________________
Kolab issue tracker <kolab-issues at intevation.de>
<https://www.intevation.de/roundup/kolab/issue3423>
___________________________________________________