org.apache.hadoop.hbase.io.hfile

Class CombinedBlockCache

java.lang.Object

org.apache.hadoop.hbase.io.hfile.CombinedBlockCache

All Implemented Interfaces:

Iterable<CachedBlock>, HeapSize, BlockCache, ResizableBlockCache

Direct Known Subclasses:

InclusiveCombinedBlockCache

@InterfaceAudience.Private
public class CombinedBlockCache
extends Object
implements ResizableBlockCache, HeapSize

CombinedBlockCache is an abstraction layer that combines LruBlockCache and BucketCache. The smaller lruCache is used to cache bloom blocks and index blocks. The larger Cache is used to cache data blocks. getBlock(BlockCacheKey, boolean, boolean, boolean) reads first from the smaller lruCache before looking for the block in the l2Cache. Metrics are the combined size and hits and misses of both caches.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	CombinedBlockCache.CombinedCacheStats

Field Summary

Fields

Modifier and Type	Field and Description
protected CombinedBlockCache.CombinedCacheStats	combinedCacheStats
protected BlockCache	l2Cache
protected LruBlockCache	onHeapCache

Constructor Summary

Constructors

Constructor and Description
CombinedBlockCache(LruBlockCache onHeapCache, BlockCache l2Cache)

Method Summary

Modifier and Type	Method and Description
void	cacheBlock(BlockCacheKey cacheKey, Cacheable buf) Add block to cache (defaults to not in-memory).
void	cacheBlock(BlockCacheKey cacheKey, Cacheable buf, boolean inMemory) Add block to cache.
boolean	evictBlock(BlockCacheKey cacheKey) Evict block from cache.
int	evictBlocksByHfileName(String hfileName) Evicts all blocks for the given HFile.
Cacheable	getBlock(BlockCacheKey cacheKey, boolean caching, boolean repeat, boolean updateCacheMetrics) Fetch block from cache.
BlockCache[]	getBlockCaches()
long	getBlockCount() Returns the number of blocks currently cached in the block cache.
long	getCurrentDataSize() Returns the occupied size of data blocks, in bytes.
long	getCurrentSize() Returns the occupied size of the block cache, in bytes.
long	getDataBlockCount() Returns the number of data blocks currently cached in the block cache.
long	getFreeSize() Returns the free size of the block cache, in bytes.
long	getMaxSize() Returns the Max size of the block cache, in bytes.
int	getRefCount(BlockCacheKey cacheKey)
CacheStats	getStats() Get the statistics for this block cache.
long	heapSize()
Iterator<CachedBlock>	iterator()
void	returnBlock(BlockCacheKey cacheKey, Cacheable block) Called when the scanner using the block decides to return the block once its usage is over.
void	setMaxSize(long size) Sets the max heap size that can be used by the BlockCache.
void	shutdown() Shutdown the cache.
long	size() Returns the total size of the block cache, in bytes.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Field Detail

onHeapCache

protected final LruBlockCache onHeapCache

l2Cache

protected final BlockCache l2Cache

combinedCacheStats

protected final CombinedBlockCache.CombinedCacheStats combinedCacheStats

Constructor Detail

CombinedBlockCache

public CombinedBlockCache(LruBlockCache onHeapCache,
                          BlockCache l2Cache)

Method Detail

heapSize

public long heapSize()

Specified by:

heapSize in interface HeapSize

Returns:

Approximate 'exclusive deep size' of implementing object. Includes count of payload and hosting object sizings.

cacheBlock

public void cacheBlock(BlockCacheKey cacheKey,
                       Cacheable buf,
                       boolean inMemory)

Description copied from interface: BlockCache

Add block to cache.

Specified by:

cacheBlock in interface BlockCache

Parameters:

cacheKey - The block's cache key.

buf - The block contents wrapped in a ByteBuffer.

inMemory - Whether block should be treated as in-memory

cacheBlock

public void cacheBlock(BlockCacheKey cacheKey,
                       Cacheable buf)

Description copied from interface: BlockCache

Add block to cache (defaults to not in-memory).

Specified by:

cacheBlock in interface BlockCache

Parameters:

cacheKey - The block's cache key.

buf - The object to cache.

getBlock

public Cacheable getBlock(BlockCacheKey cacheKey,
                          boolean caching,
                          boolean repeat,
                          boolean updateCacheMetrics)

Description copied from interface: BlockCache

Fetch block from cache.

Specified by:

getBlock in interface BlockCache

Parameters:

cacheKey - Block to fetch.

caching - Whether this request has caching enabled (used for stats)

repeat - Whether this is a repeat lookup for the same block (used to avoid double counting cache misses when doing double-check locking)

updateCacheMetrics - Whether to update cache metrics or not

Returns:

Block or null if block is not in 2 cache.

evictBlock

public boolean evictBlock(BlockCacheKey cacheKey)

Description copied from interface: BlockCache

Evict block from cache.

Specified by:

evictBlock in interface BlockCache

Parameters:

cacheKey - Block to evict

Returns:

true if block existed and was evicted, false if not

evictBlocksByHfileName

public int evictBlocksByHfileName(String hfileName)

Description copied from interface: BlockCache

Evicts all blocks for the given HFile.

Specified by:

evictBlocksByHfileName in interface BlockCache

Returns:

the number of blocks evicted

getStats

public CacheStats getStats()

Description copied from interface: BlockCache

Get the statistics for this block cache.

Specified by:

getStats in interface BlockCache

Returns:

Stats

shutdown

public void shutdown()

Description copied from interface: BlockCache

Shutdown the cache.

Specified by:

shutdown in interface BlockCache

size

public long size()

Description copied from interface: BlockCache

Returns the total size of the block cache, in bytes.

Specified by:

size in interface BlockCache

Returns:

size of cache, in bytes

getMaxSize

public long getMaxSize()

Description copied from interface: BlockCache

Returns the Max size of the block cache, in bytes.

Specified by:

getMaxSize in interface BlockCache

Returns:

size of cache, in bytes

getCurrentDataSize

public long getCurrentDataSize()

Description copied from interface: BlockCache

Returns the occupied size of data blocks, in bytes.

Specified by:

getCurrentDataSize in interface BlockCache

Returns:

occupied space in cache, in bytes

getFreeSize

public long getFreeSize()

Description copied from interface: BlockCache

Returns the free size of the block cache, in bytes.

Specified by:

getFreeSize in interface BlockCache

Returns:

free space in cache, in bytes

getCurrentSize

public long getCurrentSize()

Description copied from interface: BlockCache

Returns the occupied size of the block cache, in bytes.

Specified by:

getCurrentSize in interface BlockCache

Returns:

occupied space in cache, in bytes

getBlockCount

public long getBlockCount()

Description copied from interface: BlockCache

Returns the number of blocks currently cached in the block cache.

Specified by:

getBlockCount in interface BlockCache

Returns:

number of blocks in the cache

getDataBlockCount

public long getDataBlockCount()

Description copied from interface: BlockCache

Returns the number of data blocks currently cached in the block cache.

Specified by:

getDataBlockCount in interface BlockCache

Returns:

number of blocks in the cache

iterator

public Iterator<CachedBlock> iterator()

Specified by:

iterator in interface Iterable<CachedBlock>

Specified by:

iterator in interface BlockCache

Returns:

Iterator over the blocks in the cache.

getBlockCaches

public BlockCache[] getBlockCaches()

Specified by:

getBlockCaches in interface BlockCache

Returns:

The list of sub blockcaches that make up this one; returns null if no sub caches.

setMaxSize

public void setMaxSize(long size)

Description copied from interface: ResizableBlockCache

Sets the max heap size that can be used by the BlockCache.

Specified by:

setMaxSize in interface ResizableBlockCache

Parameters:

size - The max heap size.

returnBlock

public void returnBlock(BlockCacheKey cacheKey,
                        Cacheable block)

Description copied from interface: BlockCache

Called when the scanner using the block decides to return the block once its usage is over. This API should be called after the block is used, failing to do so may have adverse effects by preventing the blocks from being evicted because of which it will prevent new hot blocks from getting added to the block cache. The implementation of the BlockCache will decide on what to be done with the block based on the memory type of the block's Cacheable.MemoryType.

Specified by:

returnBlock in interface BlockCache

Parameters:

cacheKey - the cache key of the block

block - the hfileblock to be returned

getRefCount

public int getRefCount(BlockCacheKey cacheKey)