org.iq80.leveldb.table

Class FilterBlockBuilder

java.lang.Object

org.iq80.leveldb.table.FilterBlockBuilder

public class FilterBlockBuilder
extends Object

The filter block stores a sequence of filters, where filter i contains the output of FilterPolicy::CreateFilter() on all keys that are stored in a block whose file offset falls within the range

[ i*base ... (i+1)*base-1 ]

Currently, "base" is 2KB. So for example, if blocks X and Y start in the range [ 0KB .. 2KB-1 ], all of the keys in X and Y will be converted to a filter by calling FilterPolicy::CreateFilter(), and the resulting filter will be stored as the first filter in the filter block.

The filter block is formatted as follows:

[filter 0] [filter 1] [filter 2] ... [filter N-1]

[offset of filter 0] : 4 bytes [offset of filter 1] : 4 bytes [offset of filter 2] : 4 bytes ... [offset of filter N-1] : 4 bytes

[offset of beginning of offset array] : 4 bytes lg(base) : 1 byte

Author:

Honore Vasconcelos

Constructor Summary

Constructors

Constructor and Description
FilterBlockBuilder(FilterPolicy policy)

Method Summary

Modifier and Type	Method and Description
void	addKey(Slice key)
Slice	finish()
String	name()
void	startBlock(long blockOffset)

Methods inherited from class java.lang.Object

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

Constructor Detail

FilterBlockBuilder

public FilterBlockBuilder(FilterPolicy policy)

Method Detail

addKey

public void addKey(Slice key)

startBlock

public void startBlock(long blockOffset)

finish

public Slice finish()

name

public String name()