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bug 10716: Changed transaction level to read committed to allow for more concurrency

This commit is contained in:
Alex Huang 2011-07-20 15:54:51 -07:00
parent 06ea7338a8
commit 3ea6948645
1 changed files with 33 additions and 32 deletions
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65
utils/src/com/cloud/utils/db/Merovingian2.java
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@ -44,7 +44,7 @@ import com.cloud.utils.time.InaccurateClock;
public class Merovingian2 extends StandardMBean implements MerovingianMBean {
private static final Logger s_logger = Logger.getLogger(Merovingian2.class);
private static final String ACQUIRE_SQL = "INSERT INTO op_lock (op_lock.key, op_lock.mac, op_lock.ip, op_lock.thread, op_lock.acquired_on, waiters) VALUES (?, ?, ?, ?, ?, 1)";
private static final String INCREMENT_SQL = "UPDATE op_lock SET waiters=waiters+1 where op_lock.key=? AND op_lock.mac=? AND op_lock.ip=? AND op_lock.thread=?";
private static final String SELECT_SQL = "SELECT op_lock.key, mac, ip, thread, acquired_on, waiters FROM op_lock";
@ -56,15 +56,15 @@ public class Merovingian2 extends StandardMBean implements MerovingianMBean {
private static final String SELECT_MGMT_LOCKS_SQL = SELECT_SQL + " WHERE mac=?";
private static final String SELECT_THREAD_LOCKS_SQL = SELECT_SQL + " WHERE mac=? AND ip=?";
private static final String CLEANUP_THREAD_LOCKS_SQL = "DELETE FROM op_lock WHERE mac=? AND ip=? AND thread=?";
TimeZone s_gmtTimeZone = TimeZone.getTimeZone("GMT");
private long _msId;
private final long _msId;
private static Merovingian2 s_instance = null;
ScheduledExecutorService _executor = null;
Connection _conn = null;
private Merovingian2(long msId) {
super(MerovingianMBean.class, false);
_msId = msId;
@ -73,7 +73,7 @@ public class Merovingian2 extends StandardMBean implements MerovingianMBean {
throw new CloudRuntimeException("Unable to initialize a connection to the database for locking purposes due to " + result);
}
}
public static synchronized Merovingian2 createLockMaster(long msId) {
assert s_instance == null : "No lock can serve two masters. Either he will hate the one and love the other, or he will be devoted to the one and despise the other.";
s_instance = new Merovingian2(msId);
@ -85,11 +85,11 @@ public class Merovingian2 extends StandardMBean implements MerovingianMBean {
}
return s_instance;
}
public static Merovingian2 getLockMaster() {
return s_instance;
}
@Override
public String resetDbConnection() {
s_logger.info("Resetting the database connection for locks");
@ -100,19 +100,20 @@ public class Merovingian2 extends StandardMBean implements MerovingianMBean {
s_logger.error("Unable to close connection", th);
}
}
try {
_conn = Transaction.getStandaloneConnectionWithException();
_conn.setAutoCommit(true);
_conn.setTransactionIsolation(Connection.TRANSACTION_READ_COMMITTED);
} catch (SQLException e) {
s_logger.error("Unable to get a new db connection", e);
return "Unable to initialize a connection to the database for locking purposes: " + e;
}
if (_conn == null) {
return "Unable to initialize a connection to the database for locking purposes, shutdown this server!";
}
if (_executor != null) {
try {
_executor.shutdown();
@ -120,18 +121,18 @@ public class Merovingian2 extends StandardMBean implements MerovingianMBean {
s_logger.error("Unable to shutdown the executor", th);
}
}
_executor = Executors.newScheduledThreadPool(1, new NamedThreadFactory("LockMasterConnectionKeepAlive"));
_executor.schedule(new KeepAliveTask(), 10, TimeUnit.SECONDS);
return "Success";
}
public boolean acquire(String key, int timeInSeconds) {
Thread th = Thread.currentThread();
String threadName = th.getName();
int threadId = System.identityHashCode(th);
if (s_logger.isTraceEnabled()) {
s_logger.trace("Acquiring lck-" + key + " with wait time of " + timeInSeconds);
}
@ -157,7 +158,7 @@ public class Merovingian2 extends StandardMBean implements MerovingianMBean {
}
return false;
}
protected boolean increment(String key, String threadName, int threadId) {
PreparedStatement pstmt = null;
try {
@ -183,7 +184,7 @@ public class Merovingian2 extends StandardMBean implements MerovingianMBean {
}
}
}
protected boolean doAcquire(String key, String threadName, int threadId) {
PreparedStatement pstmt = null;
@ -218,11 +219,11 @@ public class Merovingian2 extends StandardMBean implements MerovingianMBean {
} catch (SQLException e) {
}
}
s_logger.trace("Unable to acquire lck-" + key);
return false;
}
protected Map<String, String> isLocked(String key) {
PreparedStatement pstmt = null;
ResultSet rs = null;
@ -233,7 +234,7 @@ public class Merovingian2 extends StandardMBean implements MerovingianMBean {
if (!rs.next()) {
return null;
}
return toLock(rs);
} catch (SQLException e) {
throw new CloudRuntimeException("SQL Exception on inquiry", e);
@ -250,7 +251,7 @@ public class Merovingian2 extends StandardMBean implements MerovingianMBean {
}
}
}
public void cleanupThisServer() {
cleanupForServer(_msId);
}
@ -275,7 +276,7 @@ public class Merovingian2 extends StandardMBean implements MerovingianMBean {
}
}
}
public boolean release(String key) {
PreparedStatement pstmt = null;
Thread th = Thread.currentThread();
@ -314,7 +315,7 @@ public class Merovingian2 extends StandardMBean implements MerovingianMBean {
}
}
}
protected Map<String, String> toLock(ResultSet rs) throws SQLException {
Map<String, String> map = new HashMap<String, String>();
map.put("key", rs.getString(1));
@ -324,9 +325,9 @@ public class Merovingian2 extends StandardMBean implements MerovingianMBean {
map.put("date", rs.getString(5));
map.put("count", Integer.toString(rs.getInt(6)));
return map;
}
protected List<Map<String, String>> toLocks(ResultSet rs) throws SQLException {
LinkedList<Map<String, String>> results = new LinkedList<Map<String, String>>();
while (rs.next()) {
@ -334,7 +335,7 @@ public class Merovingian2 extends StandardMBean implements MerovingianMBean {
}
return results;
}
protected List<Map<String, String>> getLocks(String sql, Long msId) {
PreparedStatement pstmt = null;
ResultSet rs = null;
@ -369,7 +370,7 @@ public class Merovingian2 extends StandardMBean implements MerovingianMBean {
public List<Map<String, String>> getLocksAcquiredByThisServer() {
return getLocks(SELECT_MGMT_LOCKS_SQL, _msId);
}
public int owns(String key) {
Thread th = Thread.currentThread();
int threadId = System.identityHashCode(th);
@ -382,7 +383,7 @@ public class Merovingian2 extends StandardMBean implements MerovingianMBean {
}
return -1;
}
public List<Map<String, String>> getLocksAcquiredBy(long msId, String threadName) {
PreparedStatement pstmt = null;
ResultSet rs = null;
@ -406,12 +407,12 @@ public class Merovingian2 extends StandardMBean implements MerovingianMBean {
}
}
}
public void cleanupThread() {
Thread th = Thread.currentThread();
String threadName = th.getName();
int threadId = System.identityHashCode(th);
PreparedStatement pstmt = null;
try {
pstmt = _conn.prepareStatement(CLEANUP_THREAD_LOCKS_SQL);
@ -431,7 +432,7 @@ public class Merovingian2 extends StandardMBean implements MerovingianMBean {
}
}
}
@Override
public boolean releaseLockAsLastResortAndIReallyKnowWhatIAmDoing(String key) {
s_logger.info("Releasing a lock from jMX lck-" + key);