----- Forwarded Message ----- > From: Simon Willnauer <[email protected]> > To: [email protected]; java-user <[email protected]>; > [email protected]; [email protected] > Cc: > Sent: Tuesday, November 15, 2011 2:50 AM > Subject: JVM Bugs affecting Lucene & Solr > > hey folks, > > we lately looked into > https://issues.apache.org/jira/browse/LUCENE-3235 again, an issue > where a class using ConcurrentHashMap hangs / deadlocks on specific > JVMs in combination with specific CPUs. It turns out its a JVM bug in > Sun / Oracle Java 1.5 as well as Java 1.6. Its apparently fixed in > 1.6.u18 so if you are running on a JVM >= 1.6.u18 you should be safe. > Yet, in older JVMs all classes using > java.util.concurrent.locks.LockSupport are vulnerable which includes > ConcurrentHashMap, ReentrantLock, CountDownLatch etc. Lucene and Solr > make use of those classes too so if you running on an older JVM you > could be affected by this bug and should either upgrade to a new JVM > or use -XX:+UseMembar to start your JVM. > > In general its a good idea to keep an eye on > http://wiki.apache.org/lucene-java/SunJavaBugs we try to keep this > up-to-date > > thanks, > > Simon
We used -XX:+UseMembar in production for a while to work around a case where monitors might miss wakeups occasionally. I seem to recall discussion on the HBase lists also. - Andy
