MAPI queries to ADS

[Brandon McCombs]

Hello,

We have a C++ application at work that uses the Outlook Object model to
access the MAPI address book for a user in a custom application. In
attempts to performance test this application we are taking the raw
libraries and making the MAPI calls to ADS. The request for data
(address book entries) is made once every 10 seconds and it seems that
after 127 of those we get an error to the effect of "the exchange server
is unavailable". I did some research and found things concerning
performance counters in PerfMon regarding the % of reads/writes/searches
of NSPI (MAPI interface to ADS) and XDS (Exchange Directory services)
but nothing referring to being able to configure in the registry
parameters associated with those interfaces (like NTDS related
parameters). Does anyone have any idea why we seemed to be limited to
127 queries from a specific user account? Other users, myself included,
were still able to access address book data by using the real address
book in Outlook so I know the server wasn't really unavailable. It's
almost like ADS had a certain number of times that a single user could
query the data to prevent DDoS attacks or something.

thanks for any input.
Brandon

 

[Guest]

Don't know if this is on the same track as your issue:
I've done a bit of queries against AD to find users and then make mapi / cdo
calls to the corresponding user account to modify things like MB permissions.
I hit a limit to the number of users MB's that I could connect to and the
number was consistent but was getting an error of something regarding MAPI
out of memory. I was using vbscript.

There appears to be a maximum number of resources that a MAPI client can use
at the same time.
Have you looked at this corresponding MS Article?
http://support.microsoft.com/default.aspx?scid=kb;en-us;830829