org.apache.hadoop.hbase.io.hfile.bucket

Class BucketAllocator

java.lang.Object

org.apache.hadoop.hbase.io.hfile.bucket.BucketAllocator

@InterfaceAudience.Private
public final class BucketAllocator
extends Object

This class is used to allocate a block with specified size and free the block when evicting. It manages an array of buckets, each bucket is associated with a size and caches elements up to this size. For a completely empty bucket, this size could be re-specified dynamically.

This class is not thread safe.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	BucketAllocator.Bucket

Field Summary

Fields

Modifier and Type	Field and Description
static int	FEWEST_ITEMS_IN_BUCKET So, what is the minimum amount of items we'll tolerate in a single bucket?

Method Summary

Modifier and Type	Method and Description
long	allocateBlock(int blockSize) Allocate a block with specified size.
int	freeBlock(long offset, int length) Free a block with the offset
int	getBucketIndex(long offset)
BucketAllocator.Bucket[]	getBuckets()
long	getFreeSize()
Set<Integer>	getLeastFilledBuckets(Set<Integer> excludedBuckets, int bucketCount) Returns a set of indices of the buckets that are least filled excluding the offsets, we also the fully free buckets for the BucketSizes where everything is empty and they only have one completely free bucket as a reserved
long	getTotalSize()
long	getUsedSize()
org.apache.hadoop.hbase.io.hfile.bucket.BucketAllocator.BucketSizeInfo	roundUpToBucketSizeInfo(int blockSize) Round up the given block size to bucket size, and get the corresponding BucketSizeInfo
int	sizeIndexOfAllocation(long offset)
int	sizeOfAllocation(long offset)
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

FEWEST_ITEMS_IN_BUCKET

public static final int FEWEST_ITEMS_IN_BUCKET

So, what is the minimum amount of items we'll tolerate in a single bucket?

See Also:

Constant Field Values

Method Detail

roundUpToBucketSizeInfo

public org.apache.hadoop.hbase.io.hfile.bucket.BucketAllocator.BucketSizeInfo roundUpToBucketSizeInfo(int blockSize)

Round up the given block size to bucket size, and get the corresponding BucketSizeInfo

toString

public String toString()

Overrides:

toString in class Object

getUsedSize

public long getUsedSize()

getFreeSize

public long getFreeSize()

getTotalSize

public long getTotalSize()

allocateBlock

public long allocateBlock(int blockSize)
                   throws CacheFullException,
                          BucketAllocatorException

Allocate a block with specified size. Return the offset

Parameters:

blockSize - size of block

Returns:

the offset in the IOEngine

Throws:

CacheFullException

BucketAllocatorException

freeBlock

public int freeBlock(long offset,
                     int length)

Free a block with the offset

Parameters:

offset - block's offset

Returns:

size freed

sizeIndexOfAllocation

public int sizeIndexOfAllocation(long offset)

sizeOfAllocation

public int sizeOfAllocation(long offset)

getBuckets

public BucketAllocator.Bucket[] getBuckets()

getBucketIndex

public int getBucketIndex(long offset)

getLeastFilledBuckets

public Set<Integer> getLeastFilledBuckets(Set<Integer> excludedBuckets,
                                          int bucketCount)

Returns a set of indices of the buckets that are least filled excluding the offsets, we also the fully free buckets for the BucketSizes where everything is empty and they only have one completely free bucket as a reserved

Parameters:

excludedBuckets - the buckets that need to be excluded due to currently being in used

bucketCount - max Number of buckets to return

Returns:

set of bucket indices which could be used for eviction