consuming ocr in a webservice

i run an app with 20 threads scanning emails attachments, i have put our ocr module into a webservice to be called from the threads,

but what i have found is that the web service will only run 2 instances at a time,  on the test app if i  create 20 threads which call the webservice then only approx 10 complete with 10 timing out,

on the webservice side, it seems to get overloaded  and the ocr engine starts to fall over and gives the following

Module initialization warning
Object reference not set to an instance of an object.
The requested function is not available, or there is no appropriate license

after restarting IIS  the webservice wil begin to process again although only 2 at a time

any help would be appreciated

 

The OCR engine cannot be used in more than one thread in the same application memory space.
In the web service itself, does the engine Startup function get called more than once in the same memory space? If yes, this will not work because you must shut it down before you call startup again.
If the different OCR processes are started up in different applications, it should work even on the same machine.


Thanks,
Ali Abo Al-Rob
LEADTOOLS Technical Support

in each thread i create a new instance to the webservice, so in theory they should be in there own memory space,

 

what i have found is that there is a connection limit on the HTTP built into a machine

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnservice/html/service07222003.asp

this can be overridden  by adding this to the app.config which solves the multiple connection limit

<system.net>

<connectionManagement>

<add address="*" maxconnection="20" />

</connectionManagement>

</system.net>

but is the same still true about only having one instance running at once ?

 

 

 

 

 

Try to serialize access to the OCR engine using a mutex for example.

Thanks,
Ali Abo Al-Rob
LEADTOOLS Technical Support

that has solved all the issues, thanks for your help