com.sleepycat.je.txn

Class ReadCommittedLocker

java.lang.Object

com.sleepycat.je.txn.Locker

com.sleepycat.je.txn.BasicLocker

com.sleepycat.je.txn.BuddyLocker

com.sleepycat.je.txn.ReadCommittedLocker

public class ReadCommittedLocker
extends BuddyLocker

Extends BuddyLocker to acquire write locks using the buddy locker (the transaction locker). This is used for ReadCommitted (Degree 2) isolation.

Field Summary

Fields inherited from class com.sleepycat.je.txn.Locker

afterWaiterHook, envImpl, id, lockManager, thread

Method Summary

Modifier and Type	Method and Description
void	addDbCleanup(DbCleanup cleanup) Write operations are handled by the buddy Txn.
void	addDeleteInfo(BIN bin) Forwards this method to the transactional buddy.
static ReadCommittedLocker	createReadCommittedLocker(EnvironmentImpl env, Locker buddy)
WriteLockInfo	getWriteLockInfo(long lsn)
boolean	isReadCommittedIsolation() Is always read-committed isolation.
boolean	isTransactional() Is always transactional because the buddy locker is transactional.
boolean	lockingRequired() ReadCommittedLockers always require locking.
protected LockResult	lockInternal(long lsn, LockType lockType, boolean noWait, boolean jumpAheadOfWaiters, DatabaseImpl database) Forwards write locks to the buddy locker (the transaction locker).
Locker	newNonTxnLocker() Returns a new ReadCommittedLocker that shares locks with this locker by virtue of both lockers only holding READ locks.
void	registerCursor(CursorImpl cursor) Forwards this method to the transactional buddy.
boolean	releaseLock(long lsn) Releases the lock from this locker, or if not owned by this locker then releases it from the buddy locker.
void	unRegisterCursor(CursorImpl cursor) Forwards this method to the transactional buddy.

Methods inherited from class com.sleepycat.je.txn.BuddyLocker

checkPreempted, createBuddyLocker, getLockTimeout, getTransaction, getTxnLocker, getTxnStartMillis, getTxnTimeout, isLocalWrite, isReplicated, isTimedOut, releaseNonTxnLocks, setLockTimeout, setOnlyAbortable, setTxnTimeout, sharesLocksWith

Methods inherited from class com.sleepycat.je.txn.BasicLocker

addLock, checkState, collectStats, createBasicLocker, createBasicLocker, generateId, getWriteOwnerLocker, isSerializableIsolation, nonTxnOperationEnd, operationEnd, preLogWithoutLock

Methods inherited from class com.sleepycat.je.txn.Locker

addOpenedDatabase, allowReleaseLockAfterLsnChange, demoteLock, disallowReplicaWrite, dumpLockTable, getDefaultNoWait, getEnvironment, getId, getImportunate, getInitialLockTimeout, getPreemptable, isReadOnly, isReadUncommittedDefault, isRolledBack, isValid, lock, lockAfterLsnChange, nonBlockingLock, openCursorHook, operationEnd, operationEnd, setClosingLocker, setDefaultNoWait, setImportunate, setPreemptable, setPreempted, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Method Detail

createReadCommittedLocker

public static ReadCommittedLocker createReadCommittedLocker(EnvironmentImpl env,
                                                            Locker buddy)
                                                     throws DatabaseException

Throws:

DatabaseException

newNonTxnLocker

public Locker newNonTxnLocker()
                       throws DatabaseException

Returns a new ReadCommittedLocker that shares locks with this locker by virtue of both lockers only holding READ locks. The buddy locker underlying both ReadCommittedLocker lockers is the same transactional locker, so WRITE locks are also shared.

Overrides:

newNonTxnLocker in class BasicLocker

Throws:

DatabaseException - from subclasses.

lockInternal

protected LockResult lockInternal(long lsn,
                                  LockType lockType,
                                  boolean noWait,
                                  boolean jumpAheadOfWaiters,
                                  DatabaseImpl database)
                           throws DatabaseException

Forwards write locks to the buddy locker (the transaction locker).

Overrides:

lockInternal in class BasicLocker

Parameters:

lsn - is the node to lock.

lockType - is the type of lock to request.

noWait - is true to override the defaultNoWait setting. If true, or if defaultNoWait is true, throws LockNotAvailableException if the lock cannot be granted without waiting.

jumpAheadOfWaiters - grant the lock before other waiters, if any.

database - is the database containing lsn.

Throws:

LockConflictException - if a blocking lock could not be acquired.

DatabaseException

See Also:

Locker.lockInternal(long, com.sleepycat.je.txn.LockType, boolean, boolean, com.sleepycat.je.dbi.DatabaseImpl)

releaseLock

public boolean releaseLock(long lsn)
                    throws DatabaseException

Releases the lock from this locker, or if not owned by this locker then releases it from the buddy locker.

Overrides:

releaseLock in class Locker

Throws:

DatabaseException

getWriteLockInfo

public WriteLockInfo getWriteLockInfo(long lsn)

Overrides:

getWriteLockInfo in class BasicLocker

Returns:

the WriteLockInfo for this node.

addDbCleanup

public void addDbCleanup(DbCleanup cleanup)

Write operations are handled by the buddy Txn.

Overrides:

addDbCleanup in class BasicLocker

addDeleteInfo

public void addDeleteInfo(BIN bin)

Forwards this method to the transactional buddy. The buddy handles write locks and therefore handles delete information.

Overrides:

addDeleteInfo in class Locker

registerCursor

public void registerCursor(CursorImpl cursor)

Forwards this method to the transactional buddy. The buddy Txn tracks cursors.

Overrides:

registerCursor in class BasicLocker

unRegisterCursor

public void unRegisterCursor(CursorImpl cursor)

Forwards this method to the transactional buddy. The buddy Txn tracks cursors.

Overrides:

unRegisterCursor in class BasicLocker

lockingRequired

public boolean lockingRequired()

ReadCommittedLockers always require locking.

Overrides:

lockingRequired in class BasicLocker

isTransactional

public boolean isTransactional()

Is always transactional because the buddy locker is transactional.

Overrides:

isTransactional in class BasicLocker

isReadCommittedIsolation

public boolean isReadCommittedIsolation()

Is always read-committed isolation.

Overrides:

isReadCommittedIsolation in class BasicLocker