sql server - SQLDependency - does not fire while being busy -

is normal behavior sqldependency onchange event not fired if thread busy?

    private void notificationonchanged(...)     {         // database results                      // simulate long process          thread.sleep(10000);     } 

during sleep add new row , notification lost after sleep expires.

must spawn new single thread work , use flag detect if new notifications arrived restart it?

this behavior artifact of implementation on ado.net notification listener. see http://rusanu.com/2008/01/04/sqldependencyonchange-callback-timing/.

the sqldependency internal thread posts waitfor(receive) not going post 1 until callback returns. have little processing possible , return in onchange event. definetely nothing blocking.

alternatively can use lower level sqlnotificationrequest lets manage everyting, including notification handling. you'll have manage everything. see http://technet.microsoft.com/en-us/library/ms190270(v=sql.105).aspx