com.yahoo.prelude.cluster

Class Hasher

java.lang.Object

com.yahoo.prelude.cluster.Hasher

public class Hasher
extends Object

Failover between multiple Vespa backends.

Author:

bratseth, Prashanth B. Bhat, Steinar Knutsen

Field Summary

Fields

Modifier and Type	Field and Description
private VespaBackEndSearcher[]	allNodes
private AtomicInteger	avoidAllQrsHitSameTld
private VespaBackEndSearcher[]	localNodes
private static Logger	log
(package private) boolean	running
private static Random	tldSeeder

Constructor Summary

Constructors

Constructor and Description
Hasher() Creates a hasher independent of the programmatic VIP API.

Method Summary

Modifier and Type	Method and Description
void	add(VespaBackEndSearcher node) Make a node available for search.
private static VespaBackEndSearcher[]	addNode(VespaBackEndSearcher node, VespaBackEndSearcher[] oldNodes)
int	getNodeCount()
void	remove(VespaBackEndSearcher node) Removes a node
private VespaBackEndSearcher[]	removeNode(VespaBackEndSearcher node, VespaBackEndSearcher[] oldNodes)
VespaBackEndSearcher	select(int trynum) Return a node, prefer local nodes, try to skip already hit nodes.
private static int	tldSeed()

Methods inherited from class java.lang.Object

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

Field Detail

running

boolean running

log

private static final Logger log

tldSeeder

private static final Random tldSeeder

allNodes

private volatile VespaBackEndSearcher[] allNodes

localNodes

private volatile VespaBackEndSearcher[] localNodes

avoidAllQrsHitSameTld

private AtomicInteger avoidAllQrsHitSameTld

Constructor Detail

Hasher

public Hasher()

Creates a hasher independent of the programmatic VIP API.

Method Detail

tldSeed

private static int tldSeed()

addNode

private static VespaBackEndSearcher[] addNode(VespaBackEndSearcher node,
                                              VespaBackEndSearcher[] oldNodes)

add

public void add(VespaBackEndSearcher node)

Make a node available for search.

Parameters:

node - the backend searcher (must never be null)

removeNode

private VespaBackEndSearcher[] removeNode(VespaBackEndSearcher node,
                                          VespaBackEndSearcher[] oldNodes)

remove

public void remove(VespaBackEndSearcher node)

Removes a node

getNodeCount

public int getNodeCount()

select

public VespaBackEndSearcher select(int trynum)

Return a node, prefer local nodes, try to skip already hit nodes.

Parameters:

trynum - hint for skipping (ignored in current implementation)

Returns:

the selected node, or null if this hasher has no nodes