private void AttemptWriteLockOnResource(object data)
{
LM_Rid_Bundle bundle = (LM_Rid_Bundle)data;
Transaction t = new Transaction();
try
{
bundle.lm.LockForWrite(t, bundle.rid);
bundle.lm.UnlockAll(t);
bundle.status = 0;
}
catch (DeadLockDetected)
{
bundle.status = 1;
}
}
public void LM_UpgradeReadLockToWriteLock2()
{
MyLM lm = new MyLM();
RID res1 = new RID();
Transaction t1 = new Transaction();
LM_Rid_Bundle param = new LM_Rid_Bundle(lm, res1);
Thread thread = new Thread(AttemptWriteLockOnResource);
lm.setDeadlockTimeout(3000); // Shorten deadlock timeout to 3 seconds speed up unit test
lm.LockForRead(t1, res1);
thread.Start(param);
Thread.Sleep(1000);
lm.LockForWrite(t1, res1);
thread.Join();
// Make sure that the second thread failed with deadlock exception.
// This should happen because the first thread is still holding either the read lock or write lock
// when the second thread trys to acquire a write lock. The second thread won't be able to steal the
// lock from the first thread because two phase locking was used when the LM upgrades the read lock
// to a write lock.
Assert.AreEqual(param.status, 1);
}
public void LM_UpgradeReadLockToWriteLock2()
{
MyLM lm = new MyLM();
RID res1 = new RID();
Transaction t1 = new Transaction();
LM_Rid_Bundle param = new LM_Rid_Bundle(lm, res1);
Thread thread = new Thread(AttemptWriteLockOnResource);
lm.setDeadlockTimeout(3000); // Shorten deadlock timeout to 3 seconds speed up unit test
lm.LockForRead(t1, res1);
thread.Start(param);
Thread.Sleep(1000);
lm.LockForWrite(t1, res1);
thread.Join();
// Make sure that the second thread failed with deadlock exception.
// This should happen because the first thread is still holding either the read lock or write lock
// when the second thread trys to acquire a write lock. The second thread won't be able to steal the
// lock from the first thread because two phase locking was used when the LM upgrades the read lock
// to a write lock.
Assert.AreEqual(param.status, 1);
}
