[jbosscache-issues] [JBoss JIRA] Work started: (JBCACHE-1555) Mvcc node peek could contain stale data

Mvcc node peek could contain stale data --------------------------------------- Key: JBCACHE-1555 URL: https://jira.jboss.org/jira/browse/JBCACHE-1555 Project: JBoss Cache Issue Type: Bug Security Level: Public(Everyone can see) Components: Locking Affects Versions: 3.2.1.GA Reporter: Galder Zamarreno Assignee: Galder Zamarreno Priority: Critical Fix For: 3.3.0.GA Attachments: Chtimi2Test.java, jbosscache.log, logging-changes.txt I've added some extra logging to the attached test case to find out where the problem is: 2009-11-06 19:37:52,762 1064 DEBUG [org.jboss.cache.mvcc.MVCCNodeHelper] (pool-1-thread-1:) Peek internal node for fqn /foo/mynode 2009-11-06 19:37:52,763 1065 DEBUG [org.jboss.cache.mvcc.MVCCNodeHelper] (pool-1-thread-1:) Peek returned UnversionedNode[ /foo/mynode data=[scalar]]@14e45b3 2009-11-06 19:37:52,763 1065 TRACE [org.jboss.cache.lock.MVCCLockManager] (pool-1-thread-1:) Attempting to lock /foo/mynode ... 2009-11-06 19:37:52,763 1065 TRACE [org.jboss.cache.commands.write.PutKeyValueCommand] (pool-1-thread-1:) Perform('GlobalTransaction:<null>:3', '/foo/mynode', k='_lockthisplease_', v='_lockthisplease_') ... 2009-11-06 19:37:52,767 1069 DEBUG [org.jboss.cache.mvcc.MVCCNodeHelper] (pool-1-thread-5:) Peek internal node for fqn /foo/mynode 2009-11-06 19:37:52,767 1069 DEBUG [org.jboss.cache.mvcc.MVCCNodeHelper] (pool-1-thread-5:) Peek returned UnversionedNode[ /foo/mynode data=[scalar]]@14e45b3 2009-11-06 19:37:52,767 1069 TRACE [org.jboss.cache.lock.MVCCLockManager] (pool-1-thread-5:) Attempting to lock /foo/mynode ... 2009-11-06 19:37:52,774 1076 TRACE [org.jboss.cache.lock.MVCCLockManager] (pool-1-thread-1:) Attempting to unlock /foo/mynode ... 2009-11-06 19:37:52,777 1079 DEBUG [org.jboss.cache.mvcc.RepeatableReadNode] (pool-1-thread-5:) underlyingNode is UnversionedNode[ /foo/mynode data=[scalar, _lockthisplease_]]@fa39d7 2009-11-06 19:37:52,777 1079 DEBUG [org.jboss.cache.mvcc.RepeatableReadNode] (pool-1-thread-5:) node is UnversionedNode[ /foo/mynode data=[scalar]]@14e45b3 2009-11-06 19:37:52,778 1080 WARN [org.jboss.cache.mvcc.RepeatableReadNode] (pool-1-thread-5:) Detected write skew on Fqn [/foo/mynode]. Another process has changed the node since we last read it!. Unable to copy node for update. pool-1-thread-5 has peeked too early! it was waiting for lock that pool-1-thread-1 one and carried with old data. In the mean time, pool-1-thread-1 wrote the data and unlocked which allowed pool-1-thread-5 to continue but it had cached data that is now stale.