When I have a large number of clients I am experiencing timeouts in the getMetadata call. There's currently no way to configure this timeout - in issue
UIMA-33, we made the client descriptor's <timeout> element apply only to the process call, so getMetadata defaults to a 1 minute timeout. With a small number of clients this is OK, but the Vinci service has a default thread pool of size 20 (also not configurable through the UIMA descriptor), so if you have more clients than this then this pool may get filled up with process requests forcing a getMetadata call to wait much longer. Probably both of these settings should be configurable.