org.apache.hadoop.hbase.io

Interface HeapSize

All Known Subinterfaces:

Cacheable, SizedCellScanner, Store

All Known Implementing Classes:

Append, BlockCacheKey, BucketCache, CombinedBlockCache, Delete, DoubleBlockCache, HFileBlock, HFileBlockIndex.BlockIndexReader, HFileContext, HRegion, HStore, Increment, KeyValue, LruBlockCache, LruCachedBlock, LruCachedBlockQueue, LruHashMap, LruHashMap.Entry, MemStore, Mutation, Put, SingleSizeCache, SlabCache, WALEdit

@InterfaceAudience.Private
public interface HeapSize

Implementations can be asked for an estimate of their size in bytes.

Useful for sizing caches. Its a given that implementation approximations do not account for 32 vs 64 bit nor for different VM implementations.

An Object's size is determined by the non-static data members in it, as well as the fixed Object overhead.

For example:

 public class SampleObject implements HeapSize {

   int [] numbers;
   int x;
 }
 

Method Summary

Methods

Modifier and Type	Method and Description
long	heapSize()

Method Detail

heapSize

long heapSize()

Returns:

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