Poor response times Office 365 SOAP API (via ews-java-api)?

Question

So recently I have been facing some very slow response times from Office 365 using (what I believe is) the SOAP API with the ews-java-api library.

The code hasnt changed at all in months, but now all of a sudden when saving, loading, auth'ing etc. with the Exchange service object I can be waiting over 30 seconds for a response!

Any ideas why or what I can do (other than switching to the REST API if possible)?

Thanks in advance, Ash.

Answer 1

[ This post does not actually give a solution, but was too long for comments, and at least gives some pointers to investigate ]

Yes, Office 365 Exchange Web Services is notoriously slow. In tests from my development environment I usually measure seconds for replies to eg a GetItem call, and I see the same with one of our clients using Office 365 for calendaring.

The period I'm talking about is at least over the past 6 months, so I'm not sure how that corresponds to your all of a sudden .

Our (Delphi) program code has the ability to sync directly with an Exchange server over EWS (SOAP) or through Outlook. In the latter case we use OLE and let Outlook do the talking with Exchange 365. Strangely enough with that client we see a remarkable speed improvement when he chooses to do the syncing through Outlook* - I have no reason why. Maybe some sort of caching or Outlook/Exchange communication uses other methods?

I have no experience with the REST API.

The Microsoft Virtual Academy has an Office 365 Performance Management training that might be useful, I haven't followed it (yet?).

You do not have control over if/how MS uses EWS throttling so that path leads nowhere...

There are tools that claim to improve Office 365 performance over a WAN, I'm not sure if these would work.

There was an issue (in 2014) with the REST API also being slow but from its replies this seems to be fixed.

_{*: We did bump into another issue with timezone conversions using that, though.}