org.apache.hadoop.hbase.master.procedure

Class MasterProcedureQueue

java.lang.Object

org.apache.hadoop.hbase.master.procedure.MasterProcedureQueue

All Implemented Interfaces:

ProcedureRunnableSet

@InterfaceAudience.Private
@InterfaceStability.Evolving
public class MasterProcedureQueue
extends Object
implements ProcedureRunnableSet

ProcedureRunnableSet for the Master Procedures. This RunnableSet tries to provide to the ProcedureExecutor procedures that can be executed without having to wait on a lock. Most of the master operations can be executed concurrently, if the they are operating on different tables (e.g. two create table can be performed at the same, time assuming table A and table B). Each procedure should implement an interface providing information for this queue. for example table related procedures should implement TableProcedureInterface. each procedure will be pushed in its own queue, and based on the operation type we may take smarter decision. e.g. we can abort all the operations preceding a delete table, or similar.

Constructor Summary

Constructors

Constructor and Description
MasterProcedureQueue(org.apache.hadoop.conf.Configuration conf, TableLockManager lockManager)

Method Summary

Methods

Modifier and Type	Method and Description
void	addBack(Procedure proc) Inserts the specified element at the end of this queue.
void	addFront(Procedure proc) Inserts the specified element at the front of this queue.
void	clear() Removes all of the elements from this collection.
void	completionCleanup(Procedure proc) The procedure in execution completed.
protected boolean	markTableAsDeleted(TableName table) Tries to remove the queue and the table-lock of the specified table.
Long	poll() Fetch one Procedure from the queue
void	releaseTableRead(TableName table) Release the read lock taken with tryAcquireTableRead()
void	releaseTableWrite(TableName table) Release the write lock taken with tryAcquireTableWrite()
void	signalAll() In case the class is blocking on poll() waiting for items to be added, this method should awake poll() and poll() should return.
int	size() Returns the number of elements in this collection.
String	toString()
boolean	tryAcquireTableRead(TableName table, String purpose) Try to acquire the read lock on the specified table.
boolean	tryAcquireTableWrite(TableName table, String purpose) Try to acquire the write lock on the specified table.
void	yield(Procedure proc) The procedure can't run at the moment.

Methods inherited from class java.lang.Object

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

Constructor Detail

MasterProcedureQueue

public MasterProcedureQueue(org.apache.hadoop.conf.Configuration conf,
                    TableLockManager lockManager)

Method Detail

addFront

public void addFront(Procedure proc)

Description copied from interface: ProcedureRunnableSet

Inserts the specified element at the front of this queue.

Specified by:

addFront in interface ProcedureRunnableSet

Parameters:

proc - the Procedure to add

addBack

public void addBack(Procedure proc)

Description copied from interface: ProcedureRunnableSet

Inserts the specified element at the end of this queue.

Specified by:

addBack in interface ProcedureRunnableSet

Parameters:

proc - the Procedure to add

yield

public void yield(Procedure proc)

Description copied from interface: ProcedureRunnableSet

The procedure can't run at the moment. add it back to the queue, giving priority to someone else.

Specified by:

yield in interface ProcedureRunnableSet

Parameters:

proc - the Procedure to add back to the list

poll

public Long poll()

Description copied from interface: ProcedureRunnableSet

Fetch one Procedure from the queue

Specified by:

poll in interface ProcedureRunnableSet

Returns:

the Procedure ID to execute, or null if nothing present.

signalAll

public void signalAll()

Description copied from interface: ProcedureRunnableSet

In case the class is blocking on poll() waiting for items to be added, this method should awake poll() and poll() should return.

Specified by:

signalAll in interface ProcedureRunnableSet

clear

public void clear()

Description copied from interface: ProcedureRunnableSet

Removes all of the elements from this collection.

Specified by:

clear in interface ProcedureRunnableSet

size

public int size()

Description copied from interface: ProcedureRunnableSet

Returns the number of elements in this collection.

Specified by:

size in interface ProcedureRunnableSet

Returns:

the number of elements in this collection.

toString

public String toString()

Overrides:

toString in class Object

completionCleanup

public void completionCleanup(Procedure proc)

Description copied from interface: ProcedureRunnableSet

The procedure in execution completed. This can be implemented to perform cleanups.

Specified by:

completionCleanup in interface ProcedureRunnableSet

Parameters:

proc - the Procedure that completed the execution.

tryAcquireTableRead

public boolean tryAcquireTableRead(TableName table,
                          String purpose)

Try to acquire the read lock on the specified table. other read operations in the table-queue may be executed concurrently, otherwise they have to wait until all the read-locks are released.

Parameters:

table - Table to lock

purpose - Human readable reason for locking the table

Returns:

true if we were able to acquire the lock on the table, otherwise false.

releaseTableRead

public void releaseTableRead(TableName table)

Release the read lock taken with tryAcquireTableRead()

Parameters:

table - the name of the table that has the read lock

tryAcquireTableWrite

public boolean tryAcquireTableWrite(TableName table,
                           String purpose)

Try to acquire the write lock on the specified table. other operations in the table-queue will be executed after the lock is released.

Parameters:

table - Table to lock

purpose - Human readable reason for locking the table

Returns:

true if we were able to acquire the lock on the table, otherwise false.

releaseTableWrite

public void releaseTableWrite(TableName table)

Release the write lock taken with tryAcquireTableWrite()

Parameters:

table - the name of the table that has the write lock

markTableAsDeleted

protected boolean markTableAsDeleted(TableName table)

Tries to remove the queue and the table-lock of the specified table. If there are new operations pending (e.g. a new create), the remove will not be performed.

Parameters:

table - the name of the table that should be marked as deleted

Returns:

true if deletion succeeded, false otherwise meaning that there are other new operations pending for that table (e.g. a new create).