exchangewebservices - Exchange Webservices Managed API - using ItemView.Offset for FindItems() hits performance of LoadPropertiesForItems method -

i'm doing little research on possible application of ews in our existing project written heavy use of mapi , found out disturbing performance of loadpropertiesforitems() method.

consider such scenario:

• we have 10000 (ten thousands) messages in inbox folder
• we want approximately 30 properties of every message see if satisfy our conditions further processing
• messages retrieved server in packs of 100 messages

so, code looks this:

        itemview itemsview = new itemview(100);          propertyset properties = new propertyset();         properties.add(emailmessageschema.from);         /*         add necessary properties...         */         properties.add(emailmessageschema.sensitivity);          finditemsresults<item> findresults;         list<emailmessage> list = new list<emailmessage>();                  {             findresults = folder.finditems(itemsview);                             _service.loadpropertiesforitems(findresults, properties);              foreach (item in findresults)             {                 ... every items             }              if (findresults.nextpageoffset.hasvalue)             {                 itemsview.offset = findresults.nextpageoffset.value;             }          }while(findresults.moreavailable); 

and problem every increment of itemsview.offset property makes loadpropertiesforitems method longer execute. first couple of iterations not noticeable around 30th time loop makes call time increases under 1 second 8 or more seconds. , memory allocation hits physical limits causing out of memory exception.

i'm pretty sure problems "offset related" because changed code little that:

        itemsview = new itemview(100, offset, offsetbasepoint.beginning);         ...rest of loop         if (findresults.nextpageoffset.hasvalue)         {             offset = findresults.nextpageoffset.value;         } 

and manipulated offset variable (declared outside of loop) in way set value on 4500 @ start , in debug mode after first iteration changed value 100. , according suspicions first call of loadpropertiesforitems took veeeery long execute , second call (with offset = 100) quick.

can confirm , maybe propose solution that?

of course can work without using offset why should i? :)

changing offset expensive because server has iterate through items beginning -- isn't possible have ordinal index messages because new messages can inserted view in order (think of view on name or subject).

paging through items once best approach.