org.apache.hadoop.hbase.mob

Class MobFileCache

java.lang.Object

org.apache.hadoop.hbase.mob.MobFileCache

@InterfaceAudience.Private
public class MobFileCache
extends Object

The cache for mob files. This cache doesn't cache the mob file blocks. It only caches the references of mob files. We are doing this to avoid opening and closing mob files all the time. We just keep references open.

Constructor Summary

Constructors

Constructor and Description
MobFileCache(org.apache.hadoop.conf.Configuration conf)

Method Summary

Methods

Modifier and Type	Method and Description
void	closeFile(MobFile file) Closes a mob file.
void	evict() Evicts the lru cached mob files when the count of the cached files is larger than the threshold.
void	evictFile(String fileName) Evicts the cached file by the name.
long	getAccessCount() Gets the count of accesses to the mob file cache.
int	getCacheSize() Gets the count of cached mob files.
long	getEvictedFileCount() Gets the number of items evicted from the mob file cache.
double	getHitRatio() Gets the hit ratio to the mob file cache.
long	getMissCount() Gets the count of misses to the mob file cache.
MobFile	openFile(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path path, MobCacheConfig cacheConf) Opens a mob file.
void	printStatistics() Prints the statistics.
void	shutdown()

Methods inherited from class java.lang.Object

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

Constructor Detail

MobFileCache

public MobFileCache(org.apache.hadoop.conf.Configuration conf)

Method Detail

evict

public void evict()

Evicts the lru cached mob files when the count of the cached files is larger than the threshold.

evictFile

public void evictFile(String fileName)

Evicts the cached file by the name.

Parameters:

fileName - The name of a cached file.

openFile

public MobFile openFile(org.apache.hadoop.fs.FileSystem fs,
               org.apache.hadoop.fs.Path path,
               MobCacheConfig cacheConf)
                 throws IOException

Opens a mob file.

Parameters:

fs - The current file system.

path - The file path.

cacheConf - The current MobCacheConfig

Returns:

A opened mob file.

Throws:

IOException

closeFile

public void closeFile(MobFile file)

Closes a mob file.

Parameters:

file - The mob file that needs to be closed.

shutdown

public void shutdown()

getCacheSize

public int getCacheSize()

Gets the count of cached mob files.

Returns:

The count of the cached mob files.

getAccessCount

public long getAccessCount()

Gets the count of accesses to the mob file cache.

Returns:

The count of accesses to the mob file cache.

getMissCount

public long getMissCount()

Gets the count of misses to the mob file cache.

Returns:

The count of misses to the mob file cache.

getEvictedFileCount

public long getEvictedFileCount()

Gets the number of items evicted from the mob file cache.

Returns:

The number of items evicted from the mob file cache.

getHitRatio

public double getHitRatio()

Gets the hit ratio to the mob file cache.

Returns:

The hit ratio to the mob file cache.

printStatistics

public void printStatistics()

Prints the statistics.