BlockDataManager
= BlockDataManager
BlockDataManager is an <
BlockDataManager uses storage:BlockId.md[] to uniquely identify blocks of data and network:ManagedBuffer.md[] to represent them.
BlockDataManager is used to initialize a storage:BlockTransferService.md#init[].
BlockDataManager is used to create a storage:NettyBlockRpcServer.md[].
== [[contract]] Contract
=== [[getBlockData]] getBlockData
[source,scala]¶
getBlockData( blockId: BlockId): ManagedBuffer
Fetches a block data (as a network:ManagedBuffer.md[]) for the given storage:BlockId.md[]
Used when:
-
NettyBlockRpcServer is requested to storage:NettyBlockRpcServer.md#OpenBlocks[handle a OpenBlocks message]
-
ShuffleBlockFetcherIterator is requested to storage:ShuffleBlockFetcherIterator.md#fetchLocalBlocks[fetchLocalBlocks]
=== [[putBlockData]] putBlockData
[source, scala]¶
putBlockData( blockId: BlockId, data: ManagedBuffer, level: StorageLevel, classTag: ClassTag[_]): Boolean
Stores (puts) a block data (as a network:ManagedBuffer.md[]) for the given storage:BlockId.md[]. Returns true when completed successfully or false when failed.
Used when NettyBlockRpcServer is requested to storage:NettyBlockRpcServer.md#UploadBlock[handle an UploadBlock message]
=== [[putBlockDataAsStream]] putBlockDataAsStream
[source, scala]¶
putBlockDataAsStream( blockId: BlockId, level: StorageLevel, classTag: ClassTag[_]): StreamCallbackWithID
Stores a block data that will be received as a stream
Used when NettyBlockRpcServer is requested to storage:NettyBlockRpcServer.md#receiveStream[receiveStream]
=== [[releaseLock]] releaseLock
[source, scala]¶
releaseLock( blockId: BlockId, taskAttemptId: Option[Long]): Unit
Releases a lock
Used when:
-
TorrentBroadcast is requested to core:TorrentBroadcast.md#releaseLock[releaseLock]
-
BlockManager is requested to storage:BlockManager.md#handleLocalReadFailure[handleLocalReadFailure], storage:BlockManager.md#getLocalValues[getLocalValues], storage:BlockManager.md#getOrElseUpdate[getOrElseUpdate], storage:BlockManager.md#doPut[doPut], and storage:BlockManager.md#releaseLockAndDispose[releaseLockAndDispose]
== [[implementations]] Available BlockDataManagers
storage:BlockManager.md[] is the default and only known BlockDataManager in Apache Spark.