alluxio.worker.block

Class TieredBlockStore

java.lang.Object

alluxio.worker.block.TieredBlockStore

All Implemented Interfaces:

LocalBlockStore, SessionCleanable, Closeable, AutoCloseable

@ThreadSafe
public class TieredBlockStore
extends Object
implements LocalBlockStore

This class represents an object store that manages all the blocks in the local tiered storage. This store exposes simple public APIs to operate blocks. Inside this store, it creates an Allocator to decide where to put a new block, an Evictor to decide where to evict a stale block, a BlockMetadataManager to maintain the status of the tiered storage, and a LockManager to coordinate read/write on the same block.

This class is thread-safe, using the following lock hierarchy to ensure thread-safety:

• Any block-level operation (e.g., read, move or remove) on an existing block must acquire a block lock for this block via mLockManager. This block lock is a read/write lock, guarding both the metadata operations and the following I/O on this block. It coordinates different threads (clients) when accessing the same block concurrently.
• Any metadata operation (read or write) must go through mMetaManager and guarded by mMetadataLock. This is also a read/write lock and coordinates different threads (clients) when accessing the shared data structure for metadata.
• Method createBlock(long, long, alluxio.worker.block.AllocateOptions) does not acquire the block lock, because it only creates a temp block which is only visible to its writer before committed (thus no concurrent access).
• Method abortBlock(long, long) does not acquire the block lock, because only temporary blocks can be aborted, and they are only visible to their writers (thus no concurrent access).
• Eviction is done in freeSpace(long, long, long, alluxio.worker.block.BlockStoreLocation) and it is on the basis of best effort. For operations that may trigger this eviction (e.g., move, create, requestSpace), retry is used

Constructor Summary

Constructors

Constructor and Description
TieredBlockStore() Creates a new instance of TieredBlockStore.
TieredBlockStore(BlockMetadataManager metaManager, BlockLockManager lockManager) Creates a new instance of TieredBlockStore.

Method Summary

Modifier and Type	Method and Description
void	abortBlock(long sessionId, long blockId) Aborts a temporary block.
void	accessBlock(long sessionId, long blockId) Notifies the block store that a block was accessed so the block store could update accordingly the registered listeners such as evictor and allocator on block access.
void	cleanupSession(long sessionId) Cleans up the data associated with a specific session (typically a dead session).
void	close()
void	commitBlock(long sessionId, long blockId, boolean pinOnCreate) Commits a temporary block to the local store.
BlockLock	commitBlockLocked(long sessionId, long blockId, boolean pinOnCreate) Similar to LocalBlockStore.commitBlock(long, long, boolean).
TempBlockMeta	createBlock(long sessionId, long blockId, AllocateOptions options) Creates the metadata of a new block and assigns a temporary path (e.g., a subdir of the final location named after session id) to store its data.
BlockReader	createBlockReader(long sessionId, long blockId, long offset) Creates a reader of an existing block to read data from this block.
BlockWriter	createBlockWriter(long sessionId, long blockId) Creates a writer to write data to a temp block.
void	freeSpace(long sessionId, long minContiguousBytes, long minAvailableBytes, BlockStoreLocation location) Free space is the entry for immediate block deletion in order to open up space for new or ongoing blocks.
BlockStoreMeta	getBlockStoreMeta() Gets the metadata of the entire store in a snapshot.
BlockStoreMeta	getBlockStoreMetaFull() Similar as LocalBlockStore.getBlockStoreMeta() except that this includes more information about the block store (e.g.
Optional<TempBlockMeta>	getTempBlockMeta(long blockId) Gets the temp metadata of a specific block from local storage.
Optional<BlockMeta>	getVolatileBlockMeta(long blockId) Gets the metadata of a block given its block id or empty if block does not exist.
boolean	hasBlockMeta(long blockId) Checks if the storage has a given block.
boolean	hasTempBlockMeta(long blockId) Checks if the storage has a given temp block.
void	moveBlock(long sessionId, long blockId, AllocateOptions moveOptions) Moves an existing block to a new location.
Optional<BlockLock>	pinBlock(long sessionId, long blockId) Pins the block indicating subsequent access.
void	registerBlockStoreEventListener(BlockStoreEventListener listener) Registers a BlockStoreEventListener to this block store.
void	removeBlock(long sessionId, long blockId) Removes an existing block.
void	removeDir(StorageDir dir) Removes a storage directory.
void	removeInaccessibleStorage() Remove Storage directories that are no longer accessible.
void	requestSpace(long sessionId, long blockId, long additionalBytes) Requests to increase the size of a temp block.
void	updatePinnedInodes(Set<Long> inodes) Updates the pinned blocks.

Methods inherited from class java.lang.Object

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

Methods inherited from interface alluxio.worker.block.LocalBlockStore

createBlockReader

Constructor Detail

TieredBlockStore

public TieredBlockStore()

Creates a new instance of TieredBlockStore.

TieredBlockStore

public TieredBlockStore(BlockMetadataManager metaManager,
                        BlockLockManager lockManager)

Creates a new instance of TieredBlockStore.

Parameters:

metaManager - the block metadata manager

lockManager - the lock manager

Method Detail

pinBlock

public Optional<BlockLock> pinBlock(long sessionId,
                                    long blockId)

Description copied from interface: LocalBlockStore

Pins the block indicating subsequent access.

Specified by:

pinBlock in interface LocalBlockStore

Parameters:

sessionId - the id of the session to lock this block

blockId - the id of the block to lock

Returns:

a lock of block to conveniently unpin the block later, or empty if the block does not exist

createBlockWriter

public BlockWriter createBlockWriter(long sessionId,
                                     long blockId)

Description copied from interface: LocalBlockStore

Creates a writer to write data to a temp block. Since the temp block is "private" to the writer, this operation requires no previously acquired lock.

Specified by:

createBlockWriter in interface LocalBlockStore

Parameters:

sessionId - the id of the session to get the writer

blockId - the id of the temp block

Returns:

a BlockWriter instance on this block

createBlockReader

public BlockReader createBlockReader(long sessionId,
                                     long blockId,
                                     long offset)
                              throws IOException

Description copied from interface: LocalBlockStore

Creates a reader of an existing block to read data from this block.

This operation requires the lock id returned by a previously acquired LocalBlockStore.pinBlock(long, long).

Specified by:

createBlockReader in interface LocalBlockStore

Parameters:

sessionId - the id of the session to get the reader

blockId - the id of an existing block

offset - the offset within the block

Returns:

a BlockReader instance on this block

Throws:

IOException

createBlock

public TempBlockMeta createBlock(long sessionId,
                                 long blockId,
                                 AllocateOptions options)

Description copied from interface: LocalBlockStore

Creates the metadata of a new block and assigns a temporary path (e.g., a subdir of the final location named after session id) to store its data. The location can be a location with specific tier and dir, or BlockStoreLocation.anyTier(), or BlockStoreLocation.anyDirInTier(String).

Before commit, all the data written to this block will be stored in the temp path and the block is only "visible" to its writer client.

Specified by:

createBlock in interface LocalBlockStore

Parameters:

sessionId - the id of the session

blockId - the id of the block to create

options - allocation options

Returns:

metadata of the temp block created

getVolatileBlockMeta

public Optional<BlockMeta> getVolatileBlockMeta(long blockId)

Description copied from interface: LocalBlockStore

Gets the metadata of a block given its block id or empty if block does not exist. This method does not require a lock id so the block is possible to be moved or removed after it returns.

Specified by:

getVolatileBlockMeta in interface LocalBlockStore

Parameters:

blockId - the block id

Returns:

metadata of the block

getTempBlockMeta

public Optional<TempBlockMeta> getTempBlockMeta(long blockId)

Description copied from interface: LocalBlockStore

Gets the temp metadata of a specific block from local storage.

Specified by:

getTempBlockMeta in interface LocalBlockStore

Parameters:

blockId - the id of the block

Returns:

metadata of the block if the temp block exists

commitBlock

public void commitBlock(long sessionId,
                        long blockId,
                        boolean pinOnCreate)

Description copied from interface: LocalBlockStore

Commits a temporary block to the local store. After commit, the block will be available in this block store for all clients to access. Since a temp block is "private" to the writer, this method requires no previously acquired lock.

Specified by:

commitBlock in interface LocalBlockStore

Parameters:

sessionId - the id of the session

blockId - the id of a temp block

pinOnCreate - whether to pin block on create

commitBlockLocked

public BlockLock commitBlockLocked(long sessionId,
                                   long blockId,
                                   boolean pinOnCreate)

Description copied from interface: LocalBlockStore

Similar to LocalBlockStore.commitBlock(long, long, boolean). It returns the block locked, so the caller is required to explicitly unlock the block. //TODO(Beinan): make this method to be private

Specified by:

commitBlockLocked in interface LocalBlockStore

Parameters:

sessionId - the id of the session

blockId - the id of a temp block

pinOnCreate - whether to pin block on create

Returns:

the lock

abortBlock

public void abortBlock(long sessionId,
                       long blockId)

Description copied from interface: LocalBlockStore

Aborts a temporary block. The metadata of this block will not be added, its data will be deleted and the space will be reclaimed. Since a temp block is "private" to the writer, this requires no previously acquired lock.

Specified by:

abortBlock in interface LocalBlockStore

Parameters:

sessionId - the id of the session

blockId - the id of a temp block

requestSpace

public void requestSpace(long sessionId,
                         long blockId,
                         long additionalBytes)

Description copied from interface: LocalBlockStore

Requests to increase the size of a temp block. Since a temp block is "private" to the writer client, this operation requires no previously acquired lock.

Specified by:

requestSpace in interface LocalBlockStore

Parameters:

sessionId - the id of the session to request space

blockId - the id of the temp block

additionalBytes - the amount of more space to request in bytes, never be less than 0

moveBlock

public void moveBlock(long sessionId,
                      long blockId,
                      AllocateOptions moveOptions)
               throws IOException

Description copied from interface: LocalBlockStore

Moves an existing block to a new location.

Specified by:

moveBlock in interface LocalBlockStore

Parameters:

sessionId - the id of the session to move a block

blockId - the id of an existing block

moveOptions - the options for move block

Throws:

IOException

removeBlock

public void removeBlock(long sessionId,
                        long blockId)
                 throws IOException

Description copied from interface: LocalBlockStore

Removes an existing block. If the block can not be found in this store.

Specified by:

removeBlock in interface LocalBlockStore

Parameters:

sessionId - the id of the session to remove a block

blockId - the id of an existing block

Throws:

IOException

accessBlock

public void accessBlock(long sessionId,
                        long blockId)

Description copied from interface: LocalBlockStore

Notifies the block store that a block was accessed so the block store could update accordingly the registered listeners such as evictor and allocator on block access.

Specified by:

accessBlock in interface LocalBlockStore

Parameters:

sessionId - the id of the session to access a block

blockId - the id of an accessed block

cleanupSession

public void cleanupSession(long sessionId)

Description copied from interface: LocalBlockStore

Cleans up the data associated with a specific session (typically a dead session). Clean up entails unlocking the block locks of this session, reclaiming space of temp blocks created by this session, and deleting the session temporary folder.

Specified by:

cleanupSession in interface LocalBlockStore

Specified by:

cleanupSession in interface SessionCleanable

Parameters:

sessionId - the session id

hasBlockMeta

public boolean hasBlockMeta(long blockId)

Description copied from interface: LocalBlockStore

Checks if the storage has a given block.

Specified by:

hasBlockMeta in interface LocalBlockStore

Parameters:

blockId - the block id

Returns:

true if the block is contained, false otherwise

hasTempBlockMeta

public boolean hasTempBlockMeta(long blockId)

Description copied from interface: LocalBlockStore

Checks if the storage has a given temp block.

Specified by:

hasTempBlockMeta in interface LocalBlockStore

Parameters:

blockId - the temp block id

Returns:

true if the block is contained, false otherwise

getBlockStoreMeta

public BlockStoreMeta getBlockStoreMeta()

Description copied from interface: LocalBlockStore

Gets the metadata of the entire store in a snapshot. There is no guarantee the state will be consistent with the snapshot after this method is called. This function should be cheap since it is called for every block.

Specified by:

getBlockStoreMeta in interface LocalBlockStore

Returns:

store metadata

getBlockStoreMetaFull

public BlockStoreMeta getBlockStoreMetaFull()

Description copied from interface: LocalBlockStore

Similar as LocalBlockStore.getBlockStoreMeta() except that this includes more information about the block store (e.g. blockId list). This is an expensive operation.

Specified by:

getBlockStoreMetaFull in interface LocalBlockStore

Returns:

full store metadata

registerBlockStoreEventListener

public void registerBlockStoreEventListener(BlockStoreEventListener listener)

Description copied from interface: LocalBlockStore

Registers a BlockStoreEventListener to this block store.

Specified by:

registerBlockStoreEventListener in interface LocalBlockStore

Parameters:

listener - the listener to those events

freeSpace

public void freeSpace(long sessionId,
                      long minContiguousBytes,
                      long minAvailableBytes,
                      BlockStoreLocation location)

Free space is the entry for immediate block deletion in order to open up space for new or ongoing blocks. - New blocks creations will not try to free space until all tiers are out of space. - Ongoing blocks could end up freeing space oftenly, when the file's origin location is low on space. This method is synchronized in order to prevent race in its only client, allocations. If not synchronized, new allocations could steal space reserved by ongoing ones. Removing synchronized requires implementing retries to this call along with an optimal locking strategy for fairness. TODO(ggezer): Remove synchronized.

Parameters:

sessionId - the session id

minContiguousBytes - the minimum amount of contiguous free space in bytes

minAvailableBytes - the minimum amount of free space in bytes

location - the location to free space

updatePinnedInodes

public void updatePinnedInodes(Set<Long> inodes)

Updates the pinned blocks.

Specified by:

updatePinnedInodes in interface LocalBlockStore

Parameters:

inodes - a set of ids inodes that are pinned

removeInaccessibleStorage

public void removeInaccessibleStorage()

Description copied from interface: LocalBlockStore

Remove Storage directories that are no longer accessible.

Specified by:

removeInaccessibleStorage in interface LocalBlockStore

removeDir

public void removeDir(StorageDir dir)

Removes a storage directory.

Parameters:

dir - storage directory to be removed

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Throws:

IOException