org.apache.flink.runtime.io.network.partition.hybrid.index

Class FileDataIndexCache<T extends FileDataIndexRegionHelper.Region>

java.lang.Object

org.apache.flink.runtime.io.network.partition.hybrid.index.FileDataIndexCache<T>

public class FileDataIndexCache<T extends FileDataIndexRegionHelper.Region>
extends Object

A cache layer of hybrid data index. This class encapsulates the logic of the index's put and get, and automatically caches some indexes in memory. When there are too many cached indexes, it is this class's responsibility to decide and eliminate some indexes to disk.

Field Summary

Fields

Modifier and Type	Field and Description
static Object	PLACEHOLDER Placeholder of cache entry's value.

Constructor Summary

Constructors

Constructor and Description
FileDataIndexCache(int numSubpartitions, Path indexFilePath, long numRetainedInMemoryRegionsMax, FileDataIndexSpilledRegionManager.Factory<T> spilledRegionManagerFactory)

Method Summary

Modifier and Type	Method and Description
void	close() Close FileDataIndexCache, this will delete the index file.
Optional<T>	get(int subpartitionId, int bufferIndex) Get a region contains target bufferIndex and belong to target subpartition.
void	put(int subpartition, List<T> fileRegions) Put regions to cache.

Methods inherited from class java.lang.Object

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

Field Detail

PLACEHOLDER

public static final Object PLACEHOLDER

Placeholder of cache entry's value. Because the cache is only used for managing region's elimination, does not need the real region as value.

Constructor Detail

FileDataIndexCache

public FileDataIndexCache(int numSubpartitions,
                          Path indexFilePath,
                          long numRetainedInMemoryRegionsMax,
                          FileDataIndexSpilledRegionManager.Factory<T> spilledRegionManagerFactory)

Method Detail

get

public Optional<T> get(int subpartitionId,
                       int bufferIndex)

Get a region contains target bufferIndex and belong to target subpartition.

Parameters:

subpartitionId - the subpartition that target buffer belong to.

bufferIndex - the index of target buffer.

Returns:

If target region can be founded from memory or disk, return optional contains target region. Otherwise, return Optional#empty();

put

public void put(int subpartition,
                List<T> fileRegions)

Put regions to cache.

Parameters:

subpartition - the subpartition's id of regions.

fileRegions - regions to be cached.

close

public void close()
           throws IOException

Close FileDataIndexCache, this will delete the index file. After that, the index can no longer be read or written.

Throws:

IOException