com.sleepycat.je.txn

Class LockManager

java.lang.Object

com.sleepycat.je.txn.LockManager

All Implemented Interfaces:

EnvConfigObserver

Direct Known Subclasses:

DummyLockManager, SyncedLockManager

public abstract class LockManager
extends Object
implements EnvConfigObserver

LockManager manages locks. Note that locks are counted as taking up part of the JE cache.

Field Summary

Fields

Modifier and Type	Field and Description
static TestHook<Void>	afterLockHook

Constructor Summary

Constructors

Constructor and Description
LockManager(EnvironmentImpl envImpl)

Method Summary

Modifier and Type	Method and Description
void	dump() Debugging
void	envConfigUpdate(DbConfigManager configMgr, EnvironmentMutableConfig ignore) Process notifications of mutable property changes.
abstract LockType	getOwnedLockType(Long lsn, Locker locker) Returns the LockType if the given locker owns a lock on the given node, or null if the lock is not owned.
abstract Set<LockInfo>	getOwners(Long lsn) Returns the Lockers that own a lock on the given LSN.
abstract List<LockInfo>	getWaiters(Long lsn) Returns the Lockers that wait on a lock on the given LSN.
abstract Locker	getWriteOwnerLocker(Long lsn)
abstract boolean	isLockUncontended(Long lsn)
StatGroup	loadStats(StatsConfig config)
LockGrantType	lock(long lsn, Locker locker, LockType type, long timeout, boolean nonBlockingRequest, boolean jumpAheadOfWaiters, DatabaseImpl database) Attempt to acquire a lock of 'type' on 'lsn'.
abstract boolean	ownsOrSharesLock(Locker locker, Long lsn)
boolean	release(long lsn, Locker locker) Release a lock and possibly notify any waiters that they have been granted the lock.
abstract LockAttemptResult	stealLock(Long lsn, Locker locker, LockType lockType)

Methods inherited from class java.lang.Object

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

Field Detail

afterLockHook

public static TestHook<Void> afterLockHook

Constructor Detail

LockManager

public LockManager(EnvironmentImpl envImpl)

Method Detail

envConfigUpdate

public void envConfigUpdate(DbConfigManager configMgr,
                            EnvironmentMutableConfig ignore)

Process notifications of mutable property changes.

Specified by:

envConfigUpdate in interface EnvConfigObserver

lock

public LockGrantType lock(long lsn,
                          Locker locker,
                          LockType type,
                          long timeout,
                          boolean nonBlockingRequest,
                          boolean jumpAheadOfWaiters,
                          DatabaseImpl database)
                   throws DatabaseException

Attempt to acquire a lock of 'type' on 'lsn'.

Parameters:

lsn - The LSN to lock.

locker - The Locker to lock this on behalf of.

type - The lock type requested.

timeout - milliseconds to time out after if lock couldn't be obtained. 0 means block indefinitely. Not used if nonBlockingRequest is true.

nonBlockingRequest - if true, means don't block if lock can't be acquired, and ignore the timeout parameter.

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

Returns:

a LockGrantType indicating whether the request was fulfilled or not. LockGrantType.NEW means the lock grant was fulfilled and the caller did not previously hold the lock. PROMOTION means the lock was granted and it was a promotion from READ to WRITE. EXISTING means the lock was already granted (not a promotion). DENIED means the lock was not granted when nonBlockingRequest is true.

Throws:

LockConflictException - if lock could not be acquired. If nonBlockingRequest is true, a LockConflictException is never thrown. Otherwise, if the lock acquisition would result in a deadlock, DeadlockException is thrown. Otherwise, if the lock timeout interval elapses and no deadlock is detected, LockTimeoutException is thrown.

DatabaseException

getOwners

public abstract Set<LockInfo> getOwners(Long lsn)

Returns the Lockers that own a lock on the given LSN. Note that when this method returns, there is nothing to prevent these lockers from releasing the lock or being closed.

getWaiters

public abstract List<LockInfo> getWaiters(Long lsn)

Returns the Lockers that wait on a lock on the given LSN.

getOwnedLockType

public abstract LockType getOwnedLockType(Long lsn,
                                          Locker locker)

Returns the LockType if the given locker owns a lock on the given node, or null if the lock is not owned.

isLockUncontended

public abstract boolean isLockUncontended(Long lsn)

ownsOrSharesLock

public abstract boolean ownsOrSharesLock(Locker locker,
                                         Long lsn)

release

public boolean release(long lsn,
                       Locker locker)
                throws DatabaseException

Release a lock and possibly notify any waiters that they have been granted the lock.

Parameters:

lsn - The LSN of the lock to release.

Returns:

true if the lock is released successfully, false if the lock is not currently being held.

Throws:

DatabaseException

getWriteOwnerLocker

public abstract Locker getWriteOwnerLocker(Long lsn)
                                    throws DatabaseException

Returns:

the transaction that owns the write lock for this

Throws:

DatabaseException

stealLock

public abstract LockAttemptResult stealLock(Long lsn,
                                            Locker locker,
                                            LockType lockType)
                                     throws DatabaseException

Throws:

DatabaseException

loadStats

public StatGroup loadStats(StatsConfig config)

dump

public void dump()
          throws DatabaseException

Debugging

Throws:

DatabaseException