Figured I'd expand the scope of this pre-announcement to find some volunteers to test the new code. If anyone wants to do it, but can't build Cayenne trunk for some reason ( http://cayenne.apache.org/building-cayenne.html ), let me know. I'll assemble the binaries.
Begin forwarded message:
From: Andrus Adamchik <and...@objectstyle.org>
Date: February 22, 2012 9:54:41 PM GMT+03:00
Subject: Non-blocking DataRowStore - need help to test
Here is a potentially disruptive change to Cayenne core:
This removes the major global lock and has a potential to significantly increase throughput (which is an issue, see CAY-1124 by Tore for instance). The implementation is based on a previously untried by us data structure - ConcurrentLinkedHashMap - http://code.google.com/p/concurrentlinkedhashmap/ . It is used by Apache Cassandra, so presumably it works and can handle the load. I internalized this code, placing it under org.apache.cayenne.util.concurrentlinkedhashmap.
I need help with testing though... Maybe someone has any kind of load tests that can emulate multiple DataContexts attached to a single ServerRuntime and performing various select/modify operations? Or maybe you are daring enough to place this in production? I will do the same on my end.
To give some reassurance, our single-threaded unit tests pass 100% with no changes after I swapped commons-collections LRUMap to ConcurrentLinkedHashMap.