Package herddb.index.blink

Class BLink<K extends Comparable<K>,V>

java.lang.Object

herddb.index.blink.BLink<K,V>

All Implemented Interfaces:

Page.Owner, AutoCloseable

public class BLink<K extends Comparable<K>,V>
extends Object
implements AutoCloseable, Page.Owner

Java implementation of b-link tree derived from Vladimir Lanin and Dennis Shasha work: A symmetric concurrent b-tree algorithm

This implementations add variable sized nodes, range scans, truncation and a way to store data pages.

For original work see:

 LANIN, Vladimir; SHASHA, Dennis. A symmetric concurrent b-tree algorithm.
 In: Proceedings of 1986 ACM Fall joint computer conference.
 IEEE Computer Society Press, 1986. p. 380-389
 

Author:

diego.salvi

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	BLink.SizeEvaluator<X,Y>	Support structure to evaluates memory byte size occupancy of keys and values

Constructor Summary

Constructors

Constructor	Description
BLink(long maxSize, BLink.SizeEvaluator<K,V> evaluator, PageReplacementPolicy policy, BLinkIndexDataStorage<K,V> storage)
BLink(long maxSize, BLink.SizeEvaluator<K,V> evaluator, PageReplacementPolicy policy, BLinkIndexDataStorage<K,V> storage, BLinkMetadata<K> metadata)

Method Summary

Modifier and Type	Method	Description
BLinkMetadata<K>	checkpoint()	Executes a complete tree checkpoint.
void	close()	Fully close the facility
V	delete(K v)
long	getUsedMemory()	Returns the actually used memory in bytes (only data currently loaded will be accounted).
V	insert(K v, V e)
boolean	insert(K v, V e, V expected)
int	nodes()	Returns the current nodes count.
Stream<Map.Entry<K,V>>	scan(K from, K to)	Supports both from and to empty.
Stream<Map.Entry<K,V>>	scan(K from, K to, boolean toInclusive)
V	search(K v)
long	size()	Returns the number of key/value pairs stored into this tree.
String	toString()
String	toStringFull()	Build a full string representation of this tree.
void	truncate()	Truncate any tree data.
void	unload(long pageId)	Unload given page from memory.

Methods inherited from class java.lang.Object

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

Constructor Detail

BLink

public BLink(long maxSize,
             BLink.SizeEvaluator<K,V> evaluator,
             PageReplacementPolicy policy,
             BLinkIndexDataStorage<K,V> storage)

BLink

public BLink(long maxSize,
             BLink.SizeEvaluator<K,V> evaluator,
             PageReplacementPolicy policy,
             BLinkIndexDataStorage<K,V> storage,
             BLinkMetadata<K> metadata)

Method Detail

close

public void close()

Fully close the facility

Specified by:

close in interface AutoCloseable

truncate

public void truncate()

Truncate any tree data. Invokers must ensure to call this method in a not concurrent way.

size

public long size()

Returns the number of key/value pairs stored into this tree.

Returns:

current size of the tree

getUsedMemory

public long getUsedMemory()

Returns the actually used memory in bytes (only data currently loaded will be accounted).

Returns:

current memory occupancy of the tree

nodes

public int nodes()

Returns the current nodes count.

Returns:

current tree nodes count

unload

public void unload(long pageId)

Description copied from interface: Page.Owner

Unload given page from memory.

Specified by:

unload in interface Page.Owner

Parameters:

pageId - id of page to be unloaded

checkpoint

public BLinkMetadata<K> checkpoint()
                            throws IOException

Executes a complete tree checkpoint.

Invoking method must ensure that there isn't any concurrent update, read operations could be executed concurrently with checkpoint.

Returns:

tree checkpoint metadata

Throws:

IOException

search

public V search(K v)

scan

public Stream<Map.Entry<K,V>> scan(K from,
                                         K to)

Supports both from and to empty.

Parameters:

from - inclusive (if not empty)

to - exclusive

Returns:

scan

public Stream<Map.Entry<K,V>> scan(K from,
                                         K to,
                                         boolean toInclusive)

insert

public boolean insert(K v,
                      V e,
                      V expected)

insert

public V insert(K v,
                V e)

delete

public V delete(K v)

toString

public String toString()

Overrides:

toString in class Object

toStringFull

public String toStringFull()

Build a full string representation of this tree.

Pay attention: it will load/unload nodes potentially polluting the page replacement policy. Use this method just for test and analysis purposes.

Returns:

full tree string representation