Package org.apache.hadoop.hbase.master.replication

Class AbstractPeerProcedure<TState>

java.lang.Object

org.apache.hadoop.hbase.procedure2.Procedure<TEnvironment>

org.apache.hadoop.hbase.procedure2.StateMachineProcedure<MasterProcedureEnv,TState>

org.apache.hadoop.hbase.master.replication.AbstractPeerProcedure<TState>

All Implemented Interfaces:

Comparable<Procedure<MasterProcedureEnv>>, PeerProcedureInterface

Direct Known Subclasses:

ModifyPeerProcedure

@Private
public abstract class AbstractPeerProcedure<TState>
extends StateMachineProcedure<MasterProcedureEnv,TState>
implements PeerProcedureInterface

The base class for all replication peer related procedure.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.hadoop.hbase.procedure2.StateMachineProcedure

StateMachineProcedure.Flow

Nested classes/interfaces inherited from class org.apache.hadoop.hbase.procedure2.Procedure

Procedure.LockState

Nested classes/interfaces inherited from interface org.apache.hadoop.hbase.master.procedure.PeerProcedureInterface

PeerProcedureInterface.PeerOperationType

Field Summary

Fields

Modifier and Type	Field	Description
protected ProcedurePrepareLatch	latch
protected String	peerId

Fields inherited from class org.apache.hadoop.hbase.procedure2.StateMachineProcedure

stateCount

Fields inherited from class org.apache.hadoop.hbase.procedure2.Procedure

NO_PROC_ID, NO_TIMEOUT

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	AbstractPeerProcedure()
protected	AbstractPeerProcedure(String peerId)

Method Summary

Modifier and Type	Method	Description
protected Procedure.LockState	acquireLock(MasterProcedureEnv env)	The user should override this method if they need a lock on an Entity.
protected final void	checkPeerModificationEnabled(MasterProcedureEnv env)
protected void	deserializeStateData(ProcedureStateSerializer serializer)	Called on store load to allow the user to decode the previously serialized state.
ProcedurePrepareLatch	getLatch()
String	getPeerId()
protected boolean	holdLock(MasterProcedureEnv env)	Used to keep the procedure lock even when the procedure is yielding or suspended.
protected void	releaseLock(MasterProcedureEnv env)	The user should override this method, and release lock if necessary.
protected void	serializeStateData(ProcedureStateSerializer serializer)	The user-level code of the procedure may have some state to persist (e.g.
protected boolean	waitInitialized(MasterProcedureEnv env)	The Procedure.doAcquireLock(Object, ProcedureStore) will be split into two steps, first, it will call us to determine whether we need to wait for initialization, second, it will call Procedure.acquireLock(Object) to actually handle the lock for this procedure.

Methods inherited from class org.apache.hadoop.hbase.procedure2.StateMachineProcedure

abort, addChildProcedure, execute, executeFromState, failIfAborted, getCurrentState, getCurrentStateId, getCycles, getInitialState, getState, getStateId, isEofState, isRollbackSupported, isRollbackSupported, isYieldAfterExecutionStep, isYieldBeforeExecuteFromState, rollback, rollbackState, setNextState, toStringState

Methods inherited from class org.apache.hadoop.hbase.procedure2.Procedure

addStackIndex, afterReplay, beforeReplay, bypass, compareTo, completionCleanup, doExecute, doRollback, elapsedTime, getChildrenLatch, getException, getLastUpdate, getNonceKey, getOwner, getParentProcId, getProcedureMetrics, getProcId, getProcIdHashCode, getProcName, getResult, getRootProcedureId, getRootProcId, getStackIndexes, getState, getSubmittedTime, getTimeout, getTimeoutTimestamp, hasChildren, hasException, hasLock, hasOwner, hasParent, hasTimeout, haveSameParent, incChildrenLatch, isBypass, isFailed, isFinished, isInitializing, isLockedWhenLoading, isRunnable, isSuccess, isWaiting, removeStackIndex, setAbortFailure, setChildrenLatch, setExecuted, setFailure, setFailure, setLastUpdate, setNonceKey, setOwner, setOwner, setParentProcId, setProcId, setResult, setRootProcId, setStackIndexes, setState, setSubmittedTime, setTimeout, setTimeoutFailure, shouldWaitClientAck, skipPersistence, suspend, toString, toStringClass, toStringClassDetails, toStringDetails, toStringSimpleSB, updateMetricsOnFinish, updateMetricsOnSubmit, updateTimestamp, wasExecuted

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.hadoop.hbase.master.procedure.PeerProcedureInterface

getPeerOperationType

Field Details

peerId

protected String peerId

latch

protected ProcedurePrepareLatch latch

Constructor Details

AbstractPeerProcedure

protected AbstractPeerProcedure()

AbstractPeerProcedure

protected AbstractPeerProcedure(String peerId)

Method Details

getLatch

public ProcedurePrepareLatch getLatch()

getPeerId

public String getPeerId()

Specified by:

getPeerId in interface PeerProcedureInterface

waitInitialized

protected boolean waitInitialized(MasterProcedureEnv env)

Description copied from class: Procedure

The Procedure.doAcquireLock(Object, ProcedureStore) will be split into two steps, first, it will call us to determine whether we need to wait for initialization, second, it will call Procedure.acquireLock(Object) to actually handle the lock for this procedure.

This is because that when master restarts, we need to restore the lock state for all the procedures to not break the semantic if Procedure.holdLock(Object) is true. But the ProcedureExecutor will be started before the master finish initialization(as it is part of the initialization!), so we need to split the code into two steps, and when restore, we just restore the lock part and ignore the waitInitialized part. Otherwise there will be dead lock.

Overrides:

waitInitialized in class Procedure<MasterProcedureEnv>

Returns:

true means we need to wait until the environment has been initialized, otherwise true.

acquireLock

protected Procedure.LockState acquireLock(MasterProcedureEnv env)

Description copied from class: Procedure

The user should override this method if they need a lock on an Entity. A lock can be anything, and it is up to the implementor. The Procedure Framework will call this method just before it invokes Procedure.execute(Object). It calls Procedure.releaseLock(Object) after the call to execute.

If you need to hold the lock for the life of the Procedure -- i.e. you do not want any other Procedure interfering while this Procedure is running, see Procedure.holdLock(Object).

Example: in our Master we can execute request in parallel for different tables. We can create t1 and create t2 and these creates can be executed at the same time. Anything else on t1/t2 is queued waiting that specific table create to happen.

There are 3 LockState:

• LOCK_ACQUIRED should be returned when the proc has the lock and the proc is ready to execute.
• LOCK_YIELD_WAIT should be returned when the proc has not the lock and the framework should take care of readding the procedure back to the runnable set for retry
• LOCK_EVENT_WAIT should be returned when the proc has not the lock and someone will take care of readding the procedure back to the runnable set when the lock is available.

Overrides:

acquireLock in class Procedure<MasterProcedureEnv>

Returns:

the lock state as described above.

releaseLock

protected void releaseLock(MasterProcedureEnv env)

Description copied from class: Procedure

The user should override this method, and release lock if necessary.

Overrides:

releaseLock in class Procedure<MasterProcedureEnv>

holdLock

protected boolean holdLock(MasterProcedureEnv env)

Description copied from class: Procedure

Used to keep the procedure lock even when the procedure is yielding or suspended.

Overrides:

holdLock in class Procedure<MasterProcedureEnv>

Returns:

true if the procedure should hold on the lock until completionCleanup()

serializeStateData

protected void serializeStateData(ProcedureStateSerializer serializer)
                           throws IOException

Description copied from class: Procedure

The user-level code of the procedure may have some state to persist (e.g. input arguments or current position in the processing state) to be able to resume on failure.

Overrides:

serializeStateData in class StateMachineProcedure<MasterProcedureEnv,TState>

Parameters:

serializer - stores the serializable state

Throws:

IOException

deserializeStateData

protected void deserializeStateData(ProcedureStateSerializer serializer)
                             throws IOException

Description copied from class: Procedure

Called on store load to allow the user to decode the previously serialized state.

Overrides:

deserializeStateData in class StateMachineProcedure<MasterProcedureEnv,TState>

Parameters:

serializer - contains the serialized state

Throws:

IOException

checkPeerModificationEnabled

protected final void checkPeerModificationEnabled(MasterProcedureEnv env)
                                           throws IOException

Throws:

IOException