MasterProcedureScheduler (Apache HBase 2.0.6 API)

java.lang.Object
- org.apache.hadoop.hbase.procedure2.AbstractProcedureScheduler
- - org.apache.hadoop.hbase.master.procedure.MasterProcedureScheduler

All Implemented Interfaces:

ProcedureScheduler
```
@InterfaceAudience.Private
public class MasterProcedureScheduler
extends AbstractProcedureScheduler
```
ProcedureScheduler for the Master Procedures. This ProcedureScheduler 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 they are operating on different tables (e.g. two create table procedures can be performed at the same time) or against two different servers; say two servers that crashed at about the same time.
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 make smarter decisions: e.g. we can abort all the operations preceding a delete table, or similar.
Concurrency control
Concurrent access to member variables (tableRunQueue, serverRunQueue, locking, tableMap, serverBuckets) is controlled by schedLock(). This mainly includes:
- AbstractProcedureScheduler.push(Procedure, boolean, boolean): A push will add a Queue back to run-queue when:
  1. Queue was empty before push (so must have been out of run-queue)
  2. Child procedure is added (which means parent procedure holds exclusive lock, and it must have moved Queue out of run-queue)
- AbstractProcedureScheduler.poll(long): A poll will remove a Queue from run-queue when:
  1. Queue becomes empty after poll
  2. Exclusive lock is requested by polled procedure and lock is available (returns the procedure)
  3. Exclusive lock is requested but lock is not available (returns null)
  4. Polled procedure is child of parent holding exclusive lock and the next procedure is not a child
- Namespace/table/region locks: Queue is added back to run-queue when lock being released is:
  1. Exclusive lock
  2. Last shared lock (in case queue was removed because next procedure in queue required exclusive lock)

Field Summary

Fields
Modifier and Type	Field and Description
`private SchemaLocking`	`locking`
`private static org.slf4j.Logger`	`LOG`
`private static AvlUtil.AvlKeyComparator<MetaQueue>`	`META_QUEUE_KEY_COMPARATOR`
`private MetaQueue`	`metaMap`
`private FairQueue<TableName>`	`metaRunQueue`
`private static AvlUtil.AvlKeyComparator<ServerQueue>`	`SERVER_QUEUE_KEY_COMPARATOR`
`private ServerQueue[]`	`serverBuckets`
`private FairQueue<ServerName>`	`serverRunQueue`
`private static AvlUtil.AvlKeyComparator<TableQueue>`	`TABLE_QUEUE_KEY_COMPARATOR`
`private TableQueue`	`tableMap`
`private FairQueue<TableName>`	`tableRunQueue`

Constructor Summary

Constructors
Constructor and Description

MasterProcedureScheduler(Function<Long,Procedure<?>> procedureRetriever)

Constructors
Constructor and Description
`MasterProcedureScheduler(Function<Long,Procedure<?>> procedureRetriever)`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`private static <T extends Comparable<T>> void`	`addToRunQueue(FairQueue<T> fairq, Queue<T> queue, Supplier<String> reason)`
`void`	`clear()` Clear current state of scheduler such that it is equivalent to newly created scheduler.
`private <T extends Comparable<T>,TNode extends Queue<T>> void`	`clear(TNode treeMap, FairQueue<T> fairq, AvlUtil.AvlKeyComparator<TNode> comparator)`
`private void`	`clearQueue()`
`void`	`completionCleanup(Procedure proc)` The procedure in execution completed.
`protected Procedure`	`dequeue(boolean onlyUrgent)`
`private <T extends Comparable<T>> void`	`doAdd(FairQueue<T> fairq, Queue<T> queue, Procedure<?> proc, boolean addFront)`
`private <T extends Comparable<T>> Procedure<?>`	`doPoll(FairQueue<T> fairq)`
`String`	`dumpLocks()` For debugging.
`protected void`	`enqueue(Procedure proc, boolean addFront)` Add the procedure to the queue.
`private static int`	`getBucketIndex(Object[] buckets, int hashCode)`
`LockedResource`	`getLockResource(LockedResourceType resourceType, String resourceName)`
`List<LockedResource>`	`getLocks()` List lock queues.
`private MetaQueue`	`getMetaQueue()`
`private static ServerName`	`getServerName(Procedure proc)`
`private ServerQueue`	`getServerQueue(ServerName serverName, ServerProcedureInterface proc)`
`private static TableName`	`getTableName(Procedure proc)`
`private TableQueue`	`getTableQueue(TableName tableName)`
`private <T extends Comparable<T>> boolean`	`isLockReady(Procedure<?> proc, Queue<T> rq)`
`private static boolean`	`isMetaProcedure(Procedure<?> proc)`
`private static boolean`	`isServerProcedure(Procedure proc)`
`private static boolean`	`isTableProcedure(Procedure proc)`
`private void`	`logLockedResource(LockedResourceType resourceType, String resourceName)` Get lock info for a resource of specified type and name and log details
`(package private) boolean`	`markTableAsDeleted(TableName table, Procedure<?> procedure)` Tries to remove the queue and the table-lock of the specified table.
`protected boolean`	`queueHasRunnables()` Returns true if there are procedures available to process.
`protected int`	`queueSize()` Returns the number of elements in this queue.
`private int`	`queueSize(Queue<?> head)`
`private static <T extends Comparable<T>> void`	`removeFromRunQueue(FairQueue<T> fairq, Queue<T> queue, Supplier<String> reason)`
`private void`	`removeServerQueue(ServerName serverName)`
`private void`	`removeTableQueue(TableName tableName)`
`private void`	`tryCleanupServerQueue(ServerName serverName, Procedure<?> proc)`
`boolean`	`waitMetaExclusiveLock(Procedure<?> procedure)` Deprecated. only used for `RecoverMetaProcedure`. Should be removed along with `RecoverMetaProcedure`.
`boolean`	`waitNamespaceExclusiveLock(Procedure<?> procedure, String namespace)` Suspend the procedure if the specified namespace is already locked.
`boolean`	`waitRegion(Procedure<?> procedure, RegionInfo regionInfo)` Suspend the procedure if the specified region is already locked.
`boolean`	`waitRegions(Procedure<?> procedure, TableName table, RegionInfo... regionInfo)` Suspend the procedure if the specified set of regions are already locked.
`boolean`	`waitServerExclusiveLock(Procedure procedure, ServerName serverName)` Try to acquire the exclusive lock on the specified server.
`boolean`	`waitTableExclusiveLock(Procedure<?> procedure, TableName table)` Suspend the procedure if the specified table is already locked.
`private TableQueue`	`waitTableQueueSharedLock(Procedure<?> procedure, TableName table)`
`boolean`	`waitTableSharedLock(Procedure<?> procedure, TableName table)` Suspend the procedure if the specified table is already locked.
`void`	`wakeMetaExclusiveLock(Procedure<?> procedure)` Deprecated. only used for `RecoverMetaProcedure`. Should be removed along with `RecoverMetaProcedure`.
`void`	`wakeNamespaceExclusiveLock(Procedure<?> procedure, String namespace)` Wake the procedures waiting for the specified namespace
`void`	`wakeRegion(Procedure<?> procedure, RegionInfo regionInfo)` Wake the procedures waiting for the specified region
`void`	`wakeRegions(Procedure<?> procedure, TableName table, RegionInfo... regionInfo)` Wake the procedures waiting for the specified regions
`void`	`wakeServerExclusiveLock(Procedure procedure, ServerName serverName)` Wake the procedures waiting for the specified server
`void`	`wakeTableExclusiveLock(Procedure<?> procedure, TableName table)` Wake the procedures waiting for the specified table
`void`	`wakeTableSharedLock(Procedure<?> procedure, TableName table)` Wake the procedures waiting for the specified table
`void`	`yield(Procedure proc)` The procedure can't run at the moment.

Methods inherited from class org.apache.hadoop.hbase.procedure2.AbstractProcedureScheduler
addBack, addBack, addFront, addFront, addFront, dequeue, getNullPollCalls, getPollCalls, hasRunnables, poll, poll, poll, poll, poll, poll, push, schedLock, schedUnlock, signalAll, size, start, stop, waitProcedure, wakePollIfNeeded, wakeProcedure, wakeWaitingProcedures

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

LOG

private static final org.slf4j.Logger LOG

SERVER_QUEUE_KEY_COMPARATOR

private static final AvlUtil.AvlKeyComparator<ServerQueue> SERVER_QUEUE_KEY_COMPARATOR

TABLE_QUEUE_KEY_COMPARATOR

private static final AvlUtil.AvlKeyComparator<TableQueue> TABLE_QUEUE_KEY_COMPARATOR

META_QUEUE_KEY_COMPARATOR

private static final AvlUtil.AvlKeyComparator<MetaQueue> META_QUEUE_KEY_COMPARATOR

serverRunQueue

private final FairQueue<ServerName> serverRunQueue

tableRunQueue

private final FairQueue<TableName> tableRunQueue

metaRunQueue

private final FairQueue<TableName> metaRunQueue

serverBuckets

private final ServerQueue[] serverBuckets

tableMap
```
private TableQueue tableMap
```

metaMap
```
private MetaQueue metaMap
```

locking
```
private final SchemaLocking locking
```

Constructor Detail

MasterProcedureScheduler

public MasterProcedureScheduler(Function<Long,Procedure<?>> procedureRetriever)

Method Detail
- yield
```
public void yield(Procedure proc)
```
  Description copied from interface: ProcedureScheduler
  
  The procedure can't run at the moment. add it back to the queue, giving priority to someone else.
  
  Parameters:
  
  proc - the Procedure to add back to the list
- enqueue
```
protected void enqueue(Procedure proc,
                       boolean addFront)
```
  Description copied from class: AbstractProcedureScheduler
  
  Add the procedure to the queue. NOTE: this method is called with the sched lock held.
  
  Specified by:
  
  enqueue in class AbstractProcedureScheduler
  
  Parameters:
  
  proc - the Procedure to add
  
  addFront - true if the item should be added to the front of the queue
- doAdd
```
private <T extends Comparable<T>> void doAdd(FairQueue<T> fairq,
                                             Queue<T> queue,
                                             Procedure<?> proc,
                                             boolean addFront)
```
- queueHasRunnables
```
protected boolean queueHasRunnables()
```
  Description copied from class: AbstractProcedureScheduler
  
  Returns true if there are procedures available to process. NOTE: this method is called with the sched lock held.
  
  Specified by:
  
  queueHasRunnables in class AbstractProcedureScheduler
  
  Returns:
  
  true if there are procedures available to process, otherwise false.
- dequeue
```
protected Procedure dequeue(boolean onlyUrgent)
```
  Specified by:
  
  dequeue in class AbstractProcedureScheduler
- isLockReady
```
private <T extends Comparable<T>> boolean isLockReady(Procedure<?> proc,
                                                      Queue<T> rq)
```
- doPoll
```
private <T extends Comparable<T>> Procedure<?> doPoll(FairQueue<T> fairq)
```
- getLocks
```
public List<LockedResource> getLocks()
```
  Description copied from interface: ProcedureScheduler
  
  List lock queues.
  
  Returns:
  
  the locks
- getLockResource
```
public LockedResource getLockResource(LockedResourceType resourceType,
                                      String resourceName)
```
  Returns:
  
  LockedResource for resource of specified type & name. null if resource is not locked.
- clear
```
public void clear()
```
  Description copied from interface: ProcedureScheduler
  
  Clear current state of scheduler such that it is equivalent to newly created scheduler. Used for testing failure and recovery. To emulate server crash/restart, ProcedureExecutor resets its own state and calls clear() on scheduler.
- clearQueue
```
private void clearQueue()
```
- clear
```
private <T extends Comparable<T>,TNode extends Queue<T>> void clear(TNode treeMap,
                                                                    FairQueue<T> fairq,
                                                                    AvlUtil.AvlKeyComparator<TNode> comparator)
```
- queueSize
```
private int queueSize(Queue<?> head)
```
- queueSize
```
protected int queueSize()
```
  Description copied from class: AbstractProcedureScheduler
  
  Returns the number of elements in this queue. NOTE: this method is called with the sched lock held.
  
  Specified by:
  
  queueSize in class AbstractProcedureScheduler
  
  Returns:
  
  the number of elements in this queue.
- completionCleanup
```
public void completionCleanup(Procedure proc)
```
  Description copied from interface: ProcedureScheduler
  
  The procedure in execution completed. This can be implemented to perform cleanups.
  
  Parameters:
  
  proc - the Procedure that completed the execution.
- addToRunQueue
```
private static <T extends Comparable<T>> void addToRunQueue(FairQueue<T> fairq,
                                                            Queue<T> queue,
                                                            Supplier<String> reason)
```
- removeFromRunQueue
```
private static <T extends Comparable<T>> void removeFromRunQueue(FairQueue<T> fairq,
                                                                 Queue<T> queue,
                                                                 Supplier<String> reason)
```
- getTableQueue
```
private TableQueue getTableQueue(TableName tableName)
```
- removeTableQueue
```
private void removeTableQueue(TableName tableName)
```
- isTableProcedure
```
private static boolean isTableProcedure(Procedure proc)
```
- getTableName
```
private static TableName getTableName(Procedure proc)
```
- getServerQueue
```
private ServerQueue getServerQueue(ServerName serverName,
                                   ServerProcedureInterface proc)
```
- removeServerQueue
```
private void removeServerQueue(ServerName serverName)
```
- tryCleanupServerQueue
```
private void tryCleanupServerQueue(ServerName serverName,
                                   Procedure<?> proc)
```
- getBucketIndex
```
private static int getBucketIndex(Object[] buckets,
                                  int hashCode)
```
- isServerProcedure
```
private static boolean isServerProcedure(Procedure proc)
```
- getServerName
```
private static ServerName getServerName(Procedure proc)
```
- getMetaQueue
```
private MetaQueue getMetaQueue()
```
- isMetaProcedure
```
private static boolean isMetaProcedure(Procedure<?> proc)
```
- logLockedResource
```
private void logLockedResource(LockedResourceType resourceType,
                               String resourceName)
```
  Get lock info for a resource of specified type and name and log details
- waitTableExclusiveLock
```
public boolean waitTableExclusiveLock(Procedure<?> procedure,
                                      TableName table)
```
  Suspend the procedure if the specified table is already locked. Other operations in the table-queue will be executed after the lock is released.
  
  Parameters:
  
  procedure - the procedure trying to acquire the lock
  
  table - Table to lock
  
  Returns:
  
  true if the procedure has to wait for the table to be available
- wakeTableExclusiveLock
```
public void wakeTableExclusiveLock(Procedure<?> procedure,
                                   TableName table)
```
  Wake the procedures waiting for the specified table
  
  Parameters:
  
  procedure - the procedure releasing the lock
  
  table - the name of the table that has the exclusive lock
- waitTableSharedLock
```
public boolean waitTableSharedLock(Procedure<?> procedure,
                                   TableName table)
```
  Suspend the procedure if the specified table is already locked. other "read" operations in the table-queue may be executed concurrently,
  
  Parameters:
  
  procedure - the procedure trying to acquire the lock
  
  table - Table to lock
  
  Returns:
  
  true if the procedure has to wait for the table to be available
- waitTableQueueSharedLock
```
private TableQueue waitTableQueueSharedLock(Procedure<?> procedure,
                                            TableName table)
```
- wakeTableSharedLock
```
public void wakeTableSharedLock(Procedure<?> procedure,
                                TableName table)
```
  Wake the procedures waiting for the specified table
  
  Parameters:
  
  procedure - the procedure releasing the lock
  
  table - the name of the table that has the shared lock
- markTableAsDeleted
```
boolean markTableAsDeleted(TableName table,
                           Procedure<?> procedure)
```
  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
  
  procedure - the procedure that is removing the table
  
  Returns:
  
  true if deletion succeeded, false otherwise meaning that there are other new operations pending for that table (e.g. a new create).
- waitRegion
```
public boolean waitRegion(Procedure<?> procedure,
                          RegionInfo regionInfo)
```
  Suspend the procedure if the specified region is already locked.
  
  Parameters:
  
  procedure - the procedure trying to acquire the lock on the region
  
  regionInfo - the region we are trying to lock
  
  Returns:
  
  true if the procedure has to wait for the regions to be available
- waitRegions
```
public boolean waitRegions(Procedure<?> procedure,
                           TableName table,
                           RegionInfo... regionInfo)
```
  Suspend the procedure if the specified set of regions are already locked.
  
  Parameters:
  
  procedure - the procedure trying to acquire the lock on the regions
  
  table - the table name of the regions we are trying to lock
  
  regionInfo - the list of regions we are trying to lock
  
  Returns:
  
  true if the procedure has to wait for the regions to be available
- wakeRegion
```
public void wakeRegion(Procedure<?> procedure,
                       RegionInfo regionInfo)
```
  Wake the procedures waiting for the specified region
  
  Parameters:
  
  procedure - the procedure that was holding the region
  
  regionInfo - the region the procedure was holding
- wakeRegions
```
public void wakeRegions(Procedure<?> procedure,
                        TableName table,
                        RegionInfo... regionInfo)
```
  Wake the procedures waiting for the specified regions
  
  Parameters:
  
  procedure - the procedure that was holding the regions
  
  regionInfo - the list of regions the procedure was holding
- waitNamespaceExclusiveLock
```
public boolean waitNamespaceExclusiveLock(Procedure<?> procedure,
                                          String namespace)
```
  Suspend the procedure if the specified namespace is already locked.
  
  Parameters:
  
  procedure - the procedure trying to acquire the lock
  
  namespace - Namespace to lock
  
  Returns:
  
  true if the procedure has to wait for the namespace to be available
  
  See Also:
  
  wakeNamespaceExclusiveLock(Procedure,String)
- wakeNamespaceExclusiveLock
```
public void wakeNamespaceExclusiveLock(Procedure<?> procedure,
                                       String namespace)
```
  Wake the procedures waiting for the specified namespace
  
  Parameters:
  
  procedure - the procedure releasing the lock
  
  namespace - the namespace that has the exclusive lock
  
  See Also:
  
  waitNamespaceExclusiveLock(Procedure,String)
- waitServerExclusiveLock
```
public boolean waitServerExclusiveLock(Procedure procedure,
                                       ServerName serverName)
```
  Try to acquire the exclusive lock on the specified server.
  
  Parameters:
  
  procedure - the procedure trying to acquire the lock
  
  serverName - Server to lock
  
  Returns:
  
  true if the procedure has to wait for the server to be available
  
  See Also:
  
  wakeServerExclusiveLock(Procedure,ServerName)
- wakeServerExclusiveLock
```
public void wakeServerExclusiveLock(Procedure procedure,
                                    ServerName serverName)
```
  Wake the procedures waiting for the specified server
  
  Parameters:
  
  procedure - the procedure releasing the lock
  
  serverName - the server that has the exclusive lock
  
  See Also:
  
  waitServerExclusiveLock(Procedure,ServerName)
- waitMetaExclusiveLock
```
@Deprecated
public boolean waitMetaExclusiveLock(Procedure<?> procedure)
```
  Deprecated. only used for RecoverMetaProcedure. Should be removed along with RecoverMetaProcedure.
  
  Try to acquire the exclusive lock on meta.
  
  Parameters:
  
  procedure - the procedure trying to acquire the lock
  
  Returns:
  
  true if the procedure has to wait for meta to be available
  
  See Also:
  
  wakeMetaExclusiveLock(Procedure)
- wakeMetaExclusiveLock
```
@Deprecated
public void wakeMetaExclusiveLock(Procedure<?> procedure)
```
  Deprecated. only used for RecoverMetaProcedure. Should be removed along with RecoverMetaProcedure.
  
  Wake the procedures waiting for meta.
  
  Parameters:
  
  procedure - the procedure releasing the lock
  
  See Also:
  
  waitMetaExclusiveLock(Procedure)
- dumpLocks
```
public String dumpLocks()
                 throws IOException
```
  For debugging. Expensive.
  
  Throws:
  
  IOException

Class MasterProcedureScheduler

Concurrency control

Field Summary

Constructor Summary

Method Summary

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

Methods inherited from class java.lang.Object

Field Detail

LOG

SERVER_QUEUE_KEY_COMPARATOR

TABLE_QUEUE_KEY_COMPARATOR

META_QUEUE_KEY_COMPARATOR

serverRunQueue

tableRunQueue

metaRunQueue

serverBuckets

tableMap

metaMap

locking

Constructor Detail

MasterProcedureScheduler

Method Detail

yield

enqueue

doAdd

queueHasRunnables

dequeue

isLockReady

doPoll

getLocks

getLockResource

clear

clearQueue

clear

queueSize

queueSize

completionCleanup

addToRunQueue

removeFromRunQueue

getTableQueue

removeTableQueue

isTableProcedure

getTableName

getServerQueue

removeServerQueue

tryCleanupServerQueue

getBucketIndex

isServerProcedure

getServerName

getMetaQueue

isMetaProcedure

logLockedResource

waitTableExclusiveLock

wakeTableExclusiveLock

waitTableSharedLock

waitTableQueueSharedLock

wakeTableSharedLock

markTableAsDeleted

waitRegion

waitRegions

wakeRegion

wakeRegions

waitNamespaceExclusiveLock

wakeNamespaceExclusiveLock

waitServerExclusiveLock

wakeServerExclusiveLock

waitMetaExclusiveLock

wakeMetaExclusiveLock

dumpLocks