Package org.elasticsearch.gateway

Class GatewayMetaState

java.lang.Object

org.elasticsearch.gateway.GatewayMetaState

All Implemented Interfaces:

ClusterStateApplier, CoordinationState.PersistedState

public class GatewayMetaState
extends java.lang.Object
implements ClusterStateApplier, CoordinationState.PersistedState

This class is responsible for storing/retrieving metadata to/from disk. When instance of this class is created, constructor ensures that this version is compatible with state stored on disk and performs state upgrade if necessary. Also it checks that atomic move is supported on the filesystem level, because it's a must for metadata store algorithm. Please note that the state being loaded when constructing the instance of this class is NOT the state that will be used as a ClusterState.metaData(). Instead when node is starting up, it calls getMetaData() method and if this node is elected as master, it requests metaData from other master eligible nodes. After that, master node performs re-conciliation on the gathered results, re-creates ClusterState and broadcasts this state to other nodes in the cluster.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	GatewayMetaState.IndexMetaDataAction	Action to perform with index metadata.
static class	GatewayMetaState.KeepPreviousGeneration
static class	GatewayMetaState.WriteChangedIndexMetaData
static class	GatewayMetaState.WriteNewIndexMetaData

Field Summary

Fields

Modifier and Type	Field	Description
protected boolean	incrementalWrite
protected static org.apache.logging.log4j.Logger	logger
protected ClusterState	previousClusterState
protected Manifest	previousManifest

Constructor Summary

Constructors

Constructor	Description
GatewayMetaState(Settings settings, NodeEnvironment nodeEnv, MetaStateService metaStateService, MetaDataIndexUpgradeService metaDataIndexUpgradeService, MetaDataUpgrader metaDataUpgrader, TransportService transportService, ClusterService clusterService, IndicesService indicesService)

Method Summary

Modifier and Type	Method	Description
void	applyClusterState(ClusterChangedEvent event)	Called when a new cluster state (ClusterChangedEvent.state() needs to be applied
void	applyClusterStateUpdaters()
long	getCurrentTerm()	Returns the current term
ClusterState	getLastAcceptedState()	Returns the last accepted cluster state
MetaData	getMetaData()
CoordinationState.PersistedState	getPersistedState(Settings settings, ClusterApplierService clusterApplierService)
static java.util.Set<Index>	getRelevantIndices(ClusterState state, ClusterState previousState, java.util.Set<Index> previouslyWrittenIndices)
protected boolean	isMasterOrDataNode()
static java.util.List<GatewayMetaState.IndexMetaDataAction>	resolveIndexMetaDataActions(java.util.Map<Index,java.lang.Long> previouslyWrittenIndices, java.util.Set<Index> relevantIndices, MetaData previousMetaData, MetaData newMetaData)	Returns list of GatewayMetaState.IndexMetaDataAction for each relevant index.
void	setCurrentTerm(long currentTerm)	Sets a new current term.
void	setLastAcceptedState(ClusterState clusterState)	Sets a new last accepted cluster state.
protected void	updateClusterState(ClusterState newState, ClusterState previousState)	Updates manifest and meta data on disk.
protected void	upgradeMetaData(MetaDataIndexUpgradeService metaDataIndexUpgradeService, MetaDataUpgrader metaDataUpgrader)

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.elasticsearch.cluster.coordination.CoordinationState.PersistedState

markLastAcceptedStateAsCommitted

Field Detail

logger

protected static final org.apache.logging.log4j.Logger logger

previousManifest

protected Manifest previousManifest

previousClusterState

protected ClusterState previousClusterState

incrementalWrite

protected boolean incrementalWrite

Constructor Detail

GatewayMetaState

public GatewayMetaState(Settings settings,
                        NodeEnvironment nodeEnv,
                        MetaStateService metaStateService,
                        MetaDataIndexUpgradeService metaDataIndexUpgradeService,
                        MetaDataUpgrader metaDataUpgrader,
                        TransportService transportService,
                        ClusterService clusterService,
                        IndicesService indicesService)
                 throws java.io.IOException

Throws:

java.io.IOException

Method Detail

getPersistedState

public CoordinationState.PersistedState getPersistedState(Settings settings,
                                                          ClusterApplierService clusterApplierService)

applyClusterStateUpdaters

public void applyClusterStateUpdaters()

upgradeMetaData

protected void upgradeMetaData(MetaDataIndexUpgradeService metaDataIndexUpgradeService,
                               MetaDataUpgrader metaDataUpgrader)
                        throws java.io.IOException

Throws:

java.io.IOException

isMasterOrDataNode

protected boolean isMasterOrDataNode()

getMetaData

public MetaData getMetaData()

applyClusterState

public void applyClusterState(ClusterChangedEvent event)

Description copied from interface: ClusterStateApplier

Called when a new cluster state (ClusterChangedEvent.state() needs to be applied

Specified by:

applyClusterState in interface ClusterStateApplier

getCurrentTerm

public long getCurrentTerm()

Description copied from interface: CoordinationState.PersistedState

Returns the current term

Specified by:

getCurrentTerm in interface CoordinationState.PersistedState

getLastAcceptedState

public ClusterState getLastAcceptedState()

Description copied from interface: CoordinationState.PersistedState

Returns the last accepted cluster state

Specified by:

getLastAcceptedState in interface CoordinationState.PersistedState

setCurrentTerm

public void setCurrentTerm(long currentTerm)

Description copied from interface: CoordinationState.PersistedState

Sets a new current term. After a successful call to this method, CoordinationState.PersistedState.getCurrentTerm() should return the last term that was set. The value returned by CoordinationState.PersistedState.getLastAcceptedState() should not be influenced by calls to this method.

Specified by:

setCurrentTerm in interface CoordinationState.PersistedState

setLastAcceptedState

public void setLastAcceptedState(ClusterState clusterState)

Description copied from interface: CoordinationState.PersistedState

Sets a new last accepted cluster state. After a successful call to this method, CoordinationState.PersistedState.getLastAcceptedState() should return the last cluster state that was set. The value returned by CoordinationState.PersistedState.getCurrentTerm() should not be influenced by calls to this method.

Specified by:

setLastAcceptedState in interface CoordinationState.PersistedState

updateClusterState

protected void updateClusterState(ClusterState newState,
                                  ClusterState previousState)
                           throws WriteStateException

Updates manifest and meta data on disk.

Parameters:

newState - new ClusterState

previousState - previous ClusterState

Throws:

WriteStateException - if exception occurs. See also WriteStateException.isDirty().

getRelevantIndices

public static java.util.Set<Index> getRelevantIndices(ClusterState state,
                                                      ClusterState previousState,
                                                      java.util.Set<Index> previouslyWrittenIndices)

resolveIndexMetaDataActions

public static java.util.List<GatewayMetaState.IndexMetaDataAction> resolveIndexMetaDataActions(java.util.Map<Index,java.lang.Long> previouslyWrittenIndices,
                                                                                               java.util.Set<Index> relevantIndices,
                                                                                               MetaData previousMetaData,
                                                                                               MetaData newMetaData)

Returns list of GatewayMetaState.IndexMetaDataAction for each relevant index. For each relevant index there are 3 options:

1. GatewayMetaState.KeepPreviousGeneration - index metadata is already stored to disk and index metadata version is not changed, no action is required.
2. GatewayMetaState.WriteNewIndexMetaData - there is no index metadata on disk and index metadata for this index should be written.
3. GatewayMetaState.WriteChangedIndexMetaData - index metadata is already on disk, but index metadata version has changed. Updated index metadata should be written to disk.

Parameters:

previouslyWrittenIndices - A list of indices for which the state was already written before

relevantIndices - The list of indices for which state should potentially be written

previousMetaData - The last meta data we know of

newMetaData - The new metadata

Returns:

list of GatewayMetaState.IndexMetaDataAction for each relevant index.