[jboss-jira] [JBoss JIRA] Created: (JGRP-384) DistributedLockManager.unlock() throws an exception if one of the group members terminates.
DistributedLockManager.unlock() throws an exception if one of the group members
terminates.
-------------------------------------------------------------------------------------------
Key: JGRP-384
URL: http://jira.jboss.com/jira/browse/JGRP-384
Project: JGroups
Issue Type: Bug
Affects Versions: 2.4
Environment: Suse Linux 10.1 Desktop
java version "1.5.0_07"
Dell Optiplex GX280
Reporter: Sean Landis
Assigned To: Bela Ban
I am trying to use the DLM to implement a failover mechanism. Two
identical processes are started. One acquires the lock and becomes the
primary; the other can't acquire the lock and becomes the backup. The
primary does it's processing. The backup checks periodically if it can
get the lock. Should the primary fail, the backup will acquire the
lock and do the processing.
This works fine. The problem I am having is if both are running, the
backup fails, and the primary tries to unlock. I get the following
stack trace:
Exception in thread "main"
org.jgroups.blocks.LockNotReleasedException: Lock cannot be unlocked.
at
org.jgroups.blocks.DistributedLockManager.unlock(DistributedLockManager.java:318)
at
org.jgroups.blocks.DistributedLockManager.unlock(DistributedLockManager.java:260)
at com.overstock.distlock.examples.FailoverTest.doIt(FailoverTest.java:50)
at com.overstock.distlock.examples.FailoverTest.main(FailoverTest.java:61)
I am running version 2.4. Here's a sample program:
package distlock.examples;
import org.jgroups.JChannel;
import org.jgroups.blocks.DistributedLockManager;
import org.jgroups.blocks.LockNotGrantedException;
import org.jgroups.blocks.VotingAdapter;
public class FailoverTest {
public static final String SERVER_PROTOCOL_STACK =
"UDP(mcast_addr=228.3.11.76;mcast_port=12345;ip_ttl=1;"
+ "mcast_send_buf_size=150000;mcast_recv_buf_size=80000)"
+ ":PING(timeout=500;num_initial_members=1)"
+ ":FD"
+ ":VERIFY_SUSPECT(timeout=1500)"
+
":pbcast.NAKACK(gc_lag=50;retransmit_timeout=300,600,1200,2400,4800)"
+ ":UNICAST(timeout=5000)"
+ ":pbcast.STABLE(desired_avg_gossip=200)"
+ ":FRAG(frag_size=4096)"
+ ":pbcast.GMS(join_timeout=5000;join_retry_timeout=1000;"
+ "shun=false;print_local_addr=false)"
;
private void doIt() throws Exception {
JChannel channel = new JChannel(SERVER_PROTOCOL_STACK);
VotingAdapter adapter = new VotingAdapter(channel);
channel.connect("cluster");
DistributedLockManager dlm = new DistributedLockManager(adapter, "Mgr");
String lockId = "theLock";
for (int i = 0; i < 40; i++) {
while (true) {
try {
System.out.println("Trying to get lock.");
dlm.lock(lockId, channel.getLocalAddress(), 10000);
break;
} catch (LockNotGrantedException ex) {
System.out.println("Could not get lock.");
}
try {
Thread.sleep(5000);
} catch(InterruptedException ex) {
}
}
System.out.println("Got lock, sleeping.");
try {
Thread.sleep(10000);
} catch(InterruptedException ex) {
}
System.out.println("unlocking and sleeping.");
dlm.unlock(lockId, channel.getLocalAddress());
try {
Thread.sleep(5000);
} catch(InterruptedException ex) {
}
}
channel.close();
}
public static void main(String[] args) throws Exception {
System.setProperty("java.net.preferIPv4Stack", "true");
new FailoverTest().doIt();
}
}
--
This message is automatically generated by JIRA.
-
If you think it was sent incorrectly contact one of the administrators:
http://jira.jboss.com/jira/secure/Administrators.jspa
-
For more information on JIRA, see: http://www.atlassian.com/software/jira