org.apache.hadoop.hive.metastore.txn

Interface TxnLockManager

All Known Implementing Classes:

DefaultTxnLockManager

public interface TxnLockManager

Method Summary

Modifier and Type	Method and Description
LockResponse	checkLock(long extLockId, long txnId, boolean zeroWaitReadEnabled, boolean isExclusiveCTAS) Check whether a lock has been obtained.
long	enqueueLock(LockRequest rqst)
ShowLocksResponse	showLocks(ShowLocksRequest rqst) Get information on current locks.
void	unlock(UnlockRequest rqst) Unlock a lock.

Method Detail

enqueueLock

@Transactional(value="txnhandler")
long enqueueLock(LockRequest rqst)
                                             throws NoSuchTxnException,
                                                    TxnAbortedException,
                                                    MetaException

Throws:

NoSuchTxnException

TxnAbortedException

MetaException

checkLock

@Transactional(value="txnhandler",
               noRollbackFor=org.apache.hadoop.hive.metastore.api.TxnAbortedException.class)
LockResponse checkLock(long extLockId,
                                                                                                                                                       long txnId,
                                                                                                                                                       boolean zeroWaitReadEnabled,
                                                                                                                                                       boolean isExclusiveCTAS)
                                                                                                                                                throws NoSuchTxnException,
                                                                                                                                                       NoSuchLockException,
                                                                                                                                                       TxnAbortedException,
                                                                                                                                                       MetaException

Check whether a lock has been obtained. This is used after enqueueLock(LockRequest) returned a wait state.

Parameters:

extLockId -

txnId - Transaction id

zeroWaitReadEnabled -

isExclusiveCTAS -

Returns:

info on the state of the lock

Throws:

NoSuchTxnException

NoSuchLockException

TxnAbortedException

MetaException

unlock

@Transactional(value="txnhandler")
void unlock(UnlockRequest rqst)
                                        throws TxnOpenException,
                                               MetaException

Unlock a lock. It is not legal to call this if the caller is part of a txn. In that case the txn should be committed or aborted instead. (Note someday this will change since multi-statement transactions will allow unlocking in the transaction.)

Parameters:

rqst - lock to unlock

Throws:

TxnOpenException

MetaException

showLocks

@Transactional(value="txnhandler")
ShowLocksResponse showLocks(ShowLocksRequest rqst)
                                                        throws MetaException

Get information on current locks.

Parameters:

rqst - lock information to retrieve

Returns:

lock information.

Throws:

MetaException