Package org.elasticsearch.index.seqno

Class ReplicationTracker

java.lang.Object

org.elasticsearch.index.shard.AbstractIndexShardComponent

org.elasticsearch.index.seqno.ReplicationTracker

All Implemented Interfaces:

java.util.function.LongSupplier, IndexShardComponent

public class ReplicationTracker
extends AbstractIndexShardComponent
implements java.util.function.LongSupplier

This class is responsible for tracking the replication group with its progress and safety markers (local and global checkpoints). The global checkpoint is the highest sequence number for which all lower (or equal) sequence number have been processed on all shards that are currently active. Since shards count as "active" when the master starts them, and before this primary shard has been notified of this fact, we also include shards that have completed recovery. These shards have received all old operations via the recovery mechanism and are kept up to date by the various replications actions. The set of shards that are taken into account for the global checkpoint calculation are called the "in-sync shards".

The global checkpoint is maintained by the primary shard and is replicated to all the replicas (via GlobalCheckpointSyncAction).

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ReplicationTracker.CheckpointState
static class	ReplicationTracker.PrimaryContext	Represents the sequence number component of the primary context.

Field Summary

Fields inherited from class org.elasticsearch.index.shard.AbstractIndexShardComponent

deprecationLogger, indexSettings, logger, shardId

Constructor Summary

Constructors

Constructor	Description
ReplicationTracker(ShardId shardId, java.lang.String allocationId, IndexSettings indexSettings, long globalCheckpoint)	Initialize the global checkpoint service.

Method Summary

Modifier and Type	Method	Description
void	abortRelocationHandoff()	Fails a relocation handoff attempt.
void	activatePrimaryMode(long localCheckpoint)	Initializes the global checkpoint tracker in primary mode (see primaryMode.
void	activateWithPrimaryContext(ReplicationTracker.PrimaryContext primaryContext)	Activates the global checkpoint tracker in primary mode (see primaryMode.
void	completeRelocationHandoff()	Marks a relocation handoff attempt as successful.
long	getAsLong()
long	getGlobalCheckpoint()	Returns the global checkpoint for the shard.
com.carrotsearch.hppc.ObjectLongMap<java.lang.String>	getInSyncGlobalCheckpoints()	Get the local knowledge of the global checkpoints for all in-sync allocation IDs.
ReplicationGroup	getReplicationGroup()	Returns the current replication group for the shard.
ReplicationTracker.CheckpointState	getTrackedLocalCheckpointForShard(java.lang.String allocationId)	Returns the local checkpoint information tracked for a specific shard.
void	initiateTracking(java.lang.String allocationId)	Called when the recovery process for a shard has opened the engine on the target shard.
boolean	isPrimaryMode()	Returns whether the replication tracker is in primary mode, i.e., whether the current shard is acting as primary from the point of view of replication.
void	markAllocationIdAsInSync(java.lang.String allocationId, long localCheckpoint)	Marks the shard with the provided allocation ID as in-sync with the primary shard.
boolean	pendingInSync()	Whether the are shards blocking global checkpoint advancement.
ReplicationTracker.PrimaryContext	startRelocationHandoff()	Initiates a relocation handoff and returns the corresponding primary context.
void	updateFromMaster(long applyingClusterStateVersion, java.util.Set<java.lang.String> inSyncAllocationIds, IndexShardRoutingTable routingTable, java.util.Set<java.lang.String> pre60AllocationIds)	Notifies the tracker of the current allocation IDs in the cluster state.
void	updateGlobalCheckpointForShard(java.lang.String allocationId, long globalCheckpoint)	Update the local knowledge of the global checkpoint for the specified allocation ID.
void	updateGlobalCheckpointOnReplica(long globalCheckpoint, java.lang.String reason)	Updates the global checkpoint on a replica shard after it has been updated by the primary.
void	updateLocalCheckpoint(java.lang.String allocationId, long localCheckpoint)	Notifies the service to update the local checkpoint for the shard with the provided allocation ID.

Methods inherited from class org.elasticsearch.index.shard.AbstractIndexShardComponent

indexSettings, nodeName, shardId

Methods inherited from class java.lang.Object

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

Constructor Detail

ReplicationTracker

public ReplicationTracker(ShardId shardId,
                          java.lang.String allocationId,
                          IndexSettings indexSettings,
                          long globalCheckpoint)

Initialize the global checkpoint service. The specified global checkpoint should be set to the last known global checkpoint, or SequenceNumbers.UNASSIGNED_SEQ_NO.

Parameters:

shardId - the shard ID

allocationId - the allocation ID

indexSettings - the index settings

globalCheckpoint - the last known global checkpoint for this shard, or SequenceNumbers.UNASSIGNED_SEQ_NO

Method Detail

getInSyncGlobalCheckpoints

public com.carrotsearch.hppc.ObjectLongMap<java.lang.String> getInSyncGlobalCheckpoints()

Get the local knowledge of the global checkpoints for all in-sync allocation IDs.

Returns:

a map from allocation ID to the local knowledge of the global checkpoint for that allocation ID

isPrimaryMode

public boolean isPrimaryMode()

Returns whether the replication tracker is in primary mode, i.e., whether the current shard is acting as primary from the point of view of replication.

getReplicationGroup

public ReplicationGroup getReplicationGroup()

Returns the current replication group for the shard.

Returns:

the replication group

getGlobalCheckpoint

public long getGlobalCheckpoint()

Returns the global checkpoint for the shard.

Returns:

the global checkpoint

getAsLong

public long getAsLong()

Specified by:

getAsLong in interface java.util.function.LongSupplier

updateGlobalCheckpointOnReplica

public void updateGlobalCheckpointOnReplica(long globalCheckpoint,
                                            java.lang.String reason)

Updates the global checkpoint on a replica shard after it has been updated by the primary.

Parameters:

globalCheckpoint - the global checkpoint

reason - the reason the global checkpoint was updated

updateGlobalCheckpointForShard

public void updateGlobalCheckpointForShard(java.lang.String allocationId,
                                           long globalCheckpoint)

Update the local knowledge of the global checkpoint for the specified allocation ID.

Parameters:

allocationId - the allocation ID to update the global checkpoint for

globalCheckpoint - the global checkpoint

activatePrimaryMode

public void activatePrimaryMode(long localCheckpoint)

Initializes the global checkpoint tracker in primary mode (see primaryMode. Called on primary activation or promotion.

updateFromMaster

public void updateFromMaster(long applyingClusterStateVersion,
                             java.util.Set<java.lang.String> inSyncAllocationIds,
                             IndexShardRoutingTable routingTable,
                             java.util.Set<java.lang.String> pre60AllocationIds)

Notifies the tracker of the current allocation IDs in the cluster state.

Parameters:

applyingClusterStateVersion - the cluster state version being applied when updating the allocation IDs from the master

inSyncAllocationIds - the allocation IDs of the currently in-sync shard copies

routingTable - the shard routing table

pre60AllocationIds - the allocation IDs of shards that are allocated to pre-6.0 nodes

initiateTracking

public void initiateTracking(java.lang.String allocationId)

Called when the recovery process for a shard has opened the engine on the target shard. Ensures that the right data structures have been set up locally to track local checkpoint information for the shard and that the shard is added to the replication group.

Parameters:

allocationId - the allocation ID of the shard for which recovery was initiated

markAllocationIdAsInSync

public void markAllocationIdAsInSync(java.lang.String allocationId,
                                     long localCheckpoint)
                              throws java.lang.InterruptedException

Marks the shard with the provided allocation ID as in-sync with the primary shard. This method will block until the local checkpoint on the specified shard advances above the current global checkpoint.

Parameters:

allocationId - the allocation ID of the shard to mark as in-sync

localCheckpoint - the current local checkpoint on the shard

Throws:

java.lang.InterruptedException

updateLocalCheckpoint

public void updateLocalCheckpoint(java.lang.String allocationId,
                                  long localCheckpoint)

Notifies the service to update the local checkpoint for the shard with the provided allocation ID. If the checkpoint is lower than the currently known one, this is a no-op. If the allocation ID is not tracked, it is ignored.

Parameters:

allocationId - the allocation ID of the shard to update the local checkpoint for

localCheckpoint - the local checkpoint for the shard

startRelocationHandoff

public ReplicationTracker.PrimaryContext startRelocationHandoff()

Initiates a relocation handoff and returns the corresponding primary context.

abortRelocationHandoff

public void abortRelocationHandoff()

Fails a relocation handoff attempt.

completeRelocationHandoff

public void completeRelocationHandoff()

Marks a relocation handoff attempt as successful. Moves the tracker into replica mode.

activateWithPrimaryContext

public void activateWithPrimaryContext(ReplicationTracker.PrimaryContext primaryContext)

Activates the global checkpoint tracker in primary mode (see primaryMode. Called on primary relocation target during primary relocation handoff.

Parameters:

primaryContext - the primary context used to initialize the state

pendingInSync

public boolean pendingInSync()

Whether the are shards blocking global checkpoint advancement. Used by tests.

getTrackedLocalCheckpointForShard

public ReplicationTracker.CheckpointState getTrackedLocalCheckpointForShard(java.lang.String allocationId)

Returns the local checkpoint information tracked for a specific shard. Used by tests.