public void TestSnapshotIsolation()
{
BTreeDatabaseConfig dbConfig;
DatabaseEntry key, data;
DatabaseEnvironmentConfig envConfig;
Thread readThread, updateThread;
Transaction txn;
updateTxn = null;
readTxn = null;
paramDB = null;
paramEnv = null;
testName = "TestSnapshotIsolation";
testHome = testFixtureHome + "/" + testName;
Configuration.ClearDir(testHome);
/*
* Open environment with DB_MULTIVERSION
* which is required by DB_TXN_SNAPSHOT.
*/
envConfig = new DatabaseEnvironmentConfig();
envConfig.Create = true;
envConfig.UseMVCC = true;
envConfig.UseTxns = true;
envConfig.UseMPool = true;
envConfig.UseLocking = true;
envConfig.TxnTimeout = 1000;
paramEnv = DatabaseEnvironment.Open(
testHome, envConfig);
paramEnv.DetectDeadlocks(DeadlockPolicy.YOUNGEST);
/*
* Open a transactional database and put 1000 records
* into it within transaction.
*/
txn = paramEnv.BeginTransaction();
dbConfig = new BTreeDatabaseConfig();
dbConfig.Creation = CreatePolicy.IF_NEEDED;
dbConfig.UseMVCC = true;
dbConfig.Env = paramEnv;
paramDB = BTreeDatabase.Open(
testName + ".db", dbConfig, txn);
for (int i = 0; i < 256; i++)
{
key = new DatabaseEntry(
BitConverter.GetBytes(i));
data = new DatabaseEntry(
BitConverter.GetBytes(i));
paramDB.Put(key, data, txn);
}
txn.Commit();
/*
* Begin two threads, read and update thread.
* The update thread runs a update transaction
* using full read/write locking. The read thread
* set DB_TXN_SNAPSHOT on read-only cursor.
*/
readThread = new Thread(new ThreadStart(ReadTxn));
updateThread = new Thread(new ThreadStart(UpdateTxn));
updateThread.Start();
Thread.Sleep(1000);
readThread.Start();
readThread.Join();
updateThread.Join();
// Commit transacion in both two threads.
if (updateTxn != null)
updateTxn.Commit();
if (readTxn != null)
readTxn.Commit();
/*
* Confirm that the overwrite operation works.
*/
ConfirmOverwrite();
paramDB.Close();
paramEnv.Close();
}
public void MoveWithRMW(string home, string name)
{
paramEnv = null;
paramDB = null;
// Open the environment.
DatabaseEnvironmentConfig envCfg =
new DatabaseEnvironmentConfig();
envCfg.Create = true;
envCfg.FreeThreaded = true;
envCfg.UseLocking = true;
envCfg.UseLogging = true;
envCfg.UseMPool = true;
envCfg.UseTxns = true;
paramEnv = DatabaseEnvironment.Open(home, envCfg);
// Open database in transaction.
Transaction openTxn = paramEnv.BeginTransaction();
BTreeDatabaseConfig cfg = new BTreeDatabaseConfig();
cfg.Creation = CreatePolicy.ALWAYS;
cfg.Env = paramEnv;
cfg.FreeThreaded = true;
cfg.PageSize = 4096;
cfg.Duplicates = DuplicatesPolicy.UNSORTED;
paramDB = BTreeDatabase.Open(name + ".db", cfg, openTxn);
openTxn.Commit();
/*
* Put 10 different, 2 duplicate and another different
* records into database.
*/
Transaction txn = paramEnv.BeginTransaction();
for (int i = 0; i < 13; i++)
{
DatabaseEntry key, data;
if (i == 10 || i == 11)
{
key = new DatabaseEntry(
ASCIIEncoding.ASCII.GetBytes("key"));
data = new DatabaseEntry(
ASCIIEncoding.ASCII.GetBytes("data"));
}
else
{
key = new DatabaseEntry(
BitConverter.GetBytes(i));
data = new DatabaseEntry(
BitConverter.GetBytes(i));
}
paramDB.Put(key, data, txn);
}
txn.Commit();
// Get a event wait handle.
signal = new EventWaitHandle(false, EventResetMode.ManualReset);
/*
* Start RdMfWt() in two threads. RdMfWt() reads
* and writes data into database.
*/
Thread t1 = new Thread(new ThreadStart(RdMfWt));
Thread t2 = new Thread(new ThreadStart(RdMfWt));
t1.Start();
t2.Start();
/*
* Give both threads time to read before signalling
* them to write.
*/
Thread.Sleep(1000);
// Invoke the write operation in both threads.
signal.Set();
// Return the number of deadlocks.
while (t1.IsAlive || t2.IsAlive)
{
/*
* Give both threads time to write before
* counting the number of deadlocks.
*/
Thread.Sleep(1000);
uint deadlocks = paramEnv.DetectDeadlocks(
DeadlockPolicy.DEFAULT);
// Confirm that there won't be any deadlock.
Assert.AreEqual(0, deadlocks);
}
t1.Join();
t2.Join();
paramDB.Close();
paramEnv.Close();
}
public void TestDetectDeadlocks()
{
testName = "TestDetectDeadlocks";
SetUpTest(true);
// Open an environment.
DatabaseEnvironmentConfig cfg =
new DatabaseEnvironmentConfig();
cfg.Create = true;
cfg.UseTxns = true;
cfg.UseMPool = true;
cfg.UseLogging = true;
cfg.UseLocking = true;
cfg.FreeThreaded = true;
testDetectDeadlocksEnv = DatabaseEnvironment.Open(
testHome, cfg);
// Open btree database.
BTreeDatabaseConfig dbConfig = new BTreeDatabaseConfig();
dbConfig.AutoCommit = true;
dbConfig.Creation = CreatePolicy.IF_NEEDED;
dbConfig.Env = testDetectDeadlocksEnv;
dbConfig.Duplicates = DuplicatesPolicy.NONE;
dbConfig.FreeThreaded = true;
testDetectDeadlocksDB = BTreeDatabase.Open(
testName + ".db", dbConfig);
// Put one record("key", "data") into database.
testDetectDeadlocksDB.Put(
new DatabaseEntry(ASCIIEncoding.ASCII.GetBytes("key")),
new DatabaseEntry(ASCIIEncoding.ASCII.GetBytes("data")));
// Begin two threads to read and write record.
Thread thread1 = new Thread(new ThreadStart(ReadAndPutRecordThread));
Thread thread2 = new Thread(new ThreadStart(ReadAndPutRecordThread));
signal = new EventWaitHandle(false, EventResetMode.ManualReset);
thread1.Start();
thread2.Start();
// Give enough time for threads to read record.
Thread.Sleep(1000);
/*
* Let the two threads apply for write lock
* synchronously.
*/
signal.Set();
// Confirm that there is deadlock in the environment.
Thread.Sleep(1000);
uint deadlockNum = testDetectDeadlocksEnv.DetectDeadlocks(
DeadlockPolicy.DEFAULT);
Assert.Less(0, deadlockNum);
thread1.Join();
thread2.Join();
// Close all.
testDetectDeadlocksDB.Close(false);
testDetectDeadlocksEnv.Close();
}