(not sure if this is the right place for such a question, maybe move this to "DEV: GroupWise Web Service (SOAP)"?!)

It's about our email archive, which has a slow perfomance. We tracked that down to a simple search in groupwise.
In Detail: The application connects to the groupwise soap port via https as a trusted key app.
Log in to a user and descending into folders. In every folder it queries groupwise with a search for mails between a specific time frame (e.g. items where older than one year).
Here is an example of the filter: Filter[(&(modify > 2015-03-03T10:12:52.966+01:00)(&(creation < 2015-03-04T08:00:53.477Z)(&(size >= 0))))]

This searches take a very long time, about 3-5 seconds. It take the same time for folders with 500 Mails up to 10.000 mails.
Anyway, this is much too slow as we have thousands of folders which has to be checked.

Do such searches take in general so long? I'm thinking about the GW Mobility Service which also connects via SOAP...

On the other side: Seaches with the Client seems to be way faster. I have to admit that I can't use the exact filter like the above one. I can only search for a time frame but not for attributes lile "modified and creation".

Sooo, any thoughts on this?

Thanks in advance,