That is the expected behaviour, all application threads are paused during GC (CMS collector being an exception, there are smaller pauses but the application threads continue to mostly run). The number of connections that could end up being queued would depend on your acceptCount setting in the server.xml file and also the inbound request rate and the time the GC takes to complete.
The OS will queue upto acceptCount requests before it begins to ignore incoming tcp connection requests. So if your inbound request rate is 2 per second and a full GC takes 6 seconds to complete, you should have 12 (2x6) new requests waiting for you when GC completes.
Sridhar wojtekpia wrote:
During full garbage collection, Solr doesn't acknowledge incoming requests. Any requests that were received during the GC are timestamped the moment GC finishes (at least that's what my logs show). Is there a limit to how many requests can queue up during a full GC? This doesn't seem like a Solr setting, but rather a container/OS setting (I'm using Tomcat on Linux). Thanks. Wojtek
