BucketCache (Apache HBase - Server 2.1.3 API)

java.lang.Object
- org.apache.hadoop.hbase.io.hfile.bucket.BucketCache

所有已实现的接口:

Iterable<CachedBlock>, HeapSize, BlockCache
```
@InterfaceAudience.Private
public class BucketCache
extends Object
implements BlockCache, HeapSize
```
BucketCache uses BucketAllocator to allocate/free blocks, and uses BucketCache#ramCache and BucketCache#backingMap in order to determine if a given element is in the cache. The bucket cache can use on-heap or off-heap memory ByteBufferIOEngine or in a file FileIOEngine to store/read the block data.
Eviction is via a similar algorithm as used in LruBlockCache
BucketCache can be used as mainly a block cache (see CombinedBlockCache), combined with LruBlockCache to decrease CMS GC and heap fragmentation.
It also can be used as a secondary cache (e.g. using a file on ssd/fusionio to store blocks) to enlarge cache space via LruBlockCache.setVictimCache(org.apache.hadoop.hbase.io.hfile.BlockCache)

字段概要

字段
限定符和类型字段和说明

static int DEFAULT_ERROR_TOLERATION_DURATION

字段
限定符和类型	字段和说明
`static int`	`DEFAULT_ERROR_TOLERATION_DURATION`

构造器概要

构造器
构造器和说明
`BucketCache(String ioEngineName, long capacity, int blockSize, int[] bucketSizes, int writerThreadNum, int writerQLen, String persistencePath)`
`BucketCache(String ioEngineName, long capacity, int blockSize, int[] bucketSizes, int writerThreadNum, int writerQLen, String persistencePath, int ioErrorsTolerationDuration, org.apache.hadoop.conf.Configuration conf)`

方法概要

所有方法实例方法具体方法
限定符和类型	方法和说明
`void`	`cacheBlock(BlockCacheKey cacheKey, Cacheable buf)` Cache the block with the specified name and buffer.
`void`	`cacheBlock(BlockCacheKey cacheKey, Cacheable cachedItem, boolean inMemory)` Cache the block with the specified name and buffer.
`boolean`	`evictBlock(BlockCacheKey cacheKey)` Evict block from cache.
`boolean`	`evictBlock(BlockCacheKey cacheKey, boolean deletedBlock)`
`int`	`evictBlocksByHfileName(String hfileName)` Evicts all blocks for a specific HFile.
`BucketAllocator`	`getAllocator()`
`Cacheable`	`getBlock(BlockCacheKey key, boolean caching, boolean repeat, boolean updateCacheMetrics)` Get the buffer of the block with the specified key.
`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.
`String`	`getIoEngine()`
`long`	`getMaxSize()` Returns the Max size of the block cache, in bytes.
`long`	`getRealCacheSize()`
`int`	`getRefCount(BlockCacheKey cacheKey)`
`CacheStats`	`getStats()` Get the statistics for this block cache.
`long`	`heapSize()`
`Iterator<CachedBlock>`	`iterator()`
`void`	`logStats()`
`void`	`returnBlock(BlockCacheKey cacheKey, Cacheable block)` Called when the scanner using the block decides to return the block once its usage is over.
`void`	`shutdown()` Shutdown the cache.
`long`	`size()` Returns the total size of the block cache, in bytes.
`protected void`	`startWriterThreads()` Called by the constructor to start the writer threads.

从类继承的方法 java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

从接口继承的方法 java.lang.Iterable
forEach, spliterator

- 字段详细资料
  - DEFAULT_ERROR_TOLERATION_DURATION
```
public static final int DEFAULT_ERROR_TOLERATION_DURATION
```
    另请参阅:
    
    常量字段值
- 构造器详细资料
  - BucketCache
```
public BucketCache(String ioEngineName,
                   long capacity,
                   int blockSize,
                   int[] bucketSizes,
                   int writerThreadNum,
                   int writerQLen,
                   String persistencePath)
            throws FileNotFoundException,
                   IOException
```
    抛出:
    
    FileNotFoundException
    
    IOException
  - BucketCache
```
public BucketCache(String ioEngineName,
                   long capacity,
                   int blockSize,
                   int[] bucketSizes,
                   int writerThreadNum,
                   int writerQLen,
                   String persistencePath,
                   int ioErrorsTolerationDuration,
                   org.apache.hadoop.conf.Configuration conf)
            throws FileNotFoundException,
                   IOException
```
    抛出:
    
    FileNotFoundException
    
    IOException
- 方法详细资料
  - startWriterThreads
```
protected void startWriterThreads()
```
    Called by the constructor to start the writer threads. Used by tests that need to override starting the threads.
  - getMaxSize
```
public long getMaxSize()
```
    从接口复制的说明: BlockCache
    
    Returns the Max size of the block cache, in bytes.
    
    指定者:
    
    getMaxSize 在接口中 BlockCache
    
    返回:
    
    size of cache, in bytes
  - getIoEngine
```
public String getIoEngine()
```
  - cacheBlock
```
public void cacheBlock(BlockCacheKey cacheKey,
                       Cacheable buf)
```
    Cache the block with the specified name and buffer.
    
    指定者:
    
    cacheBlock 在接口中 BlockCache
    
    参数:
    
    cacheKey - block's cache key
    
    buf - block buffer
  - cacheBlock
```
public void cacheBlock(BlockCacheKey cacheKey,
                       Cacheable cachedItem,
                       boolean inMemory)
```
    Cache the block with the specified name and buffer.
    
    指定者:
    
    cacheBlock 在接口中 BlockCache
    
    参数:
    
    cacheKey - block's cache key
    
    cachedItem - block buffer
    
    inMemory - if block is in-memory
  - getBlock
```
public Cacheable getBlock(BlockCacheKey key,
                          boolean caching,
                          boolean repeat,
                          boolean updateCacheMetrics)
```
    Get the buffer of the block with the specified key.
    
    指定者:
    
    getBlock 在接口中 BlockCache
    
    参数:
    
    key - block's cache key
    
    caching - true if the caller caches blocks on cache misses
    
    repeat - Whether this is a repeat lookup for the same block
    
    updateCacheMetrics - Whether we should update cache metrics or not
    
    返回:
    
    buffer of specified cache key, or null if not in cache
  - evictBlock
```
public boolean evictBlock(BlockCacheKey cacheKey)
```
    从接口复制的说明: BlockCache
    
    Evict block from cache.
    
    指定者:
    
    evictBlock 在接口中 BlockCache
    
    参数:
    
    cacheKey - Block to evict
    
    返回:
    
    true if block existed and was evicted, false if not
  - evictBlock
```
public boolean evictBlock(BlockCacheKey cacheKey,
                          boolean deletedBlock)
```
  - logStats
```
public void logStats()
```
  - getRealCacheSize
```
public long getRealCacheSize()
```
  - shutdown
```
public void shutdown()
```
    从接口复制的说明: BlockCache
    
    Shutdown the cache.
    
    指定者:
    
    shutdown 在接口中 BlockCache
  - getStats
```
public CacheStats getStats()
```
    从接口复制的说明: BlockCache
    
    Get the statistics for this block cache.
    
    指定者:
    
    getStats 在接口中 BlockCache
    
    返回:
    
    Stats
  - getAllocator
```
public BucketAllocator getAllocator()
```
  - heapSize
```
public long heapSize()
```
    指定者:
    
    heapSize 在接口中 HeapSize
  - size
```
public long size()
```
    从接口复制的说明: BlockCache
    
    Returns the total size of the block cache, in bytes.
    
    指定者:
    
    size 在接口中 BlockCache
    
    返回:
    
    size of cache, in bytes
  - getCurrentDataSize
```
public long getCurrentDataSize()
```
    从接口复制的说明: BlockCache
    
    Returns the occupied size of data blocks, in bytes.
    
    指定者:
    
    getCurrentDataSize 在接口中 BlockCache
    
    返回:
    
    occupied space in cache, in bytes
  - getFreeSize
```
public long getFreeSize()
```
    从接口复制的说明: BlockCache
    
    Returns the free size of the block cache, in bytes.
    
    指定者:
    
    getFreeSize 在接口中 BlockCache
    
    返回:
    
    free space in cache, in bytes
  - getBlockCount
```
public long getBlockCount()
```
    从接口复制的说明: BlockCache
    
    Returns the number of blocks currently cached in the block cache.
    
    指定者:
    
    getBlockCount 在接口中 BlockCache
    
    返回:
    
    number of blocks in the cache
  - getDataBlockCount
```
public long getDataBlockCount()
```
    从接口复制的说明: BlockCache
    
    Returns the number of data blocks currently cached in the block cache.
    
    指定者:
    
    getDataBlockCount 在接口中 BlockCache
    
    返回:
    
    number of blocks in the cache
  - getCurrentSize
```
public long getCurrentSize()
```
    从接口复制的说明: BlockCache
    
    Returns the occupied size of the block cache, in bytes.
    
    指定者:
    
    getCurrentSize 在接口中 BlockCache
    
    返回:
    
    occupied space in cache, in bytes
  - evictBlocksByHfileName
```
public int evictBlocksByHfileName(String hfileName)
```
    Evicts all blocks for a specific HFile.
    This is used for evict-on-close to remove all blocks of a specific HFile.
    
    指定者:
    
    evictBlocksByHfileName 在接口中 BlockCache
    
    返回:
    
    the number of blocks evicted
  - iterator
```
public Iterator<CachedBlock> iterator()
```
    指定者:
    
    iterator 在接口中 Iterable<CachedBlock>
    
    指定者:
    
    iterator 在接口中 BlockCache
    
    返回:
    
    Iterator over the blocks in the cache.
  - getBlockCaches
```
public BlockCache[] getBlockCaches()
```
    指定者:
    
    getBlockCaches 在接口中 BlockCache
    
    返回:
    
    The list of sub blockcaches that make up this one; returns null if no sub caches.
  - returnBlock
```
public void returnBlock(BlockCacheKey cacheKey,
                        Cacheable block)
```
    从接口复制的说明: 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.
    
    指定者:
    
    returnBlock 在接口中 BlockCache
    
    参数:
    
    cacheKey - the cache key of the block
    
    block - the hfileblock to be returned
  - getRefCount
```
public int getRefCount(BlockCacheKey cacheKey)
```

类 BucketCache

字段概要

构造器概要

方法概要

从类继承的方法 java.lang.Object

从接口继承的方法 java.lang.Iterable

字段详细资料

DEFAULT_ERROR_TOLERATION_DURATION

构造器详细资料

BucketCache

BucketCache

方法详细资料

startWriterThreads

getMaxSize

getIoEngine

cacheBlock

cacheBlock

getBlock

evictBlock

evictBlock

logStats

getRealCacheSize

shutdown

getStats

getAllocator

heapSize

size

getCurrentDataSize

getFreeSize

getBlockCount

getDataBlockCount

getCurrentSize

evictBlocksByHfileName

iterator

getBlockCaches

returnBlock

getRefCount