Fast locking for mostly-read PojoCache -------------------------------------- Key: JBCACHE-658 URL: http://jira.jboss.com/jira/browse/JBCACHE-658 Project: JBoss Cache Issue Type: Feature Request Security Level: Public(Everyone can see) Components: Legacy POJO Cache Reporter: Nitzan Niv Assigned To: Manik Surtani The locking mechanism locks all the nodes in the path from the tree root to the modified node. If the cache contains a deep hierarchy of nodes (e.g., PojoCache that contains complex objects) and the usage of the cache is mostly-read the locking overhead is unnecessarilly large. To enable REPEATABLE_READ isolation level with minimal overhead (but with reduced update parallelism) just the tree root should be locked instead of the nodes-path. To define this policy as a new isloation level ("single"): Change in PessimisticLockInterceptor (line 199): else { if(isolation_level == IsolationLevel.SINGLE) {//XXX if (i == 0) { acquired=child_node.acquire(owner, lock_timeout, lock_type); } } else { if(lock_type == DataNode.LOCK_TYPE_WRITE && i == (treeNodeSize - 1)) { acquired=child_node.acquire(owner, lock_timeout, DataNode.LOCK_TYPE_WRITE); } else { acquired=child_node.acquire(owner, lock_timeout, DataNode.LOCK_TYPE_READ); } }//XXX } in LockStrategyFactory.java: if (lockingLevel == IsolationLevel.REPEATABLE_READ || lockingLevel == IsolationLevel.SINGLE) //XXX return new LockStrategyRepeatableRead(); and add the "SINGLE" isolation level to IsolationLevel.java.