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[E2007] [EWSMA] [C#]: [Unexplained, sporadic increase in Exchange Server response time (from 0.03 seconds to 15 seconds)] RRS feed

  • Question

  • I have a WCF service (hosted in IIS on W 2008 R2) that periodically scans some resource calendars for todays appointments. The poll is triggered by a service consuming one of the WCF servicecontract's operations.

    This all seems fine until at some random point in time, the Exchange Server response time jumps up from less than a second per operation to approx 15 seconds. The operations succeed but the accumulation of several 15 second delays means that my WCF operation times out. ALL EWS operations that we perform take 15 seconds - binding to a calendar, binding to a calendar item, resolving names...

    Sometimes, resetting the IIS that hosts the WCF service relieves these symtpoms immediately for a while (which makes me think it could be something my WCF operation is doing incorrectly, or something inside EWSAPI itself).

    Sometimes, the symptoms just disappear and the response time from the Exchange Server speeds back up to less than a second with no apparant action taken.

    Resetting IIS on the Exchange Server itself rarely seems to relieve the symptoms.

    I don't know where to look for what might be causing this sporadic 15 second delay in all EWS calls.


    • Edited by dwedgbury Wednesday, February 15, 2012 10:39 AM
    Monday, February 13, 2012 5:12 PM

All replies

  • Today's EWS operation duration is 1 minute 15 seconds (consistently). This follows a short period where responses took 15 seconds (consistently).

    I've tried setting ExchangeService.TraceFlags to DebugMessage to see if there is anything that will help but I get no output. TraceFlags All shows all the http headers and request/response xml but all this does is confirm the delay between the requests and the responses.

    If this is a result of some sort of throttling, how can I prove it? Are there some log files or Event Log events I should look for?

    Thursday, February 16, 2012 12:18 PM