org.elasticsearch.cluster.routing.ShardRouting Maven / Gradle / Ivy
/*
* Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
* or more contributor license agreements. Licensed under the Elastic License
* 2.0 and the Server Side Public License, v 1; you may not use this file except
* in compliance with, at your election, the Elastic License 2.0 or the Server
* Side Public License, v 1.
*/
package org.elasticsearch.cluster.routing;
import org.elasticsearch.cluster.routing.RecoverySource.ExistingStoreRecoverySource;
import org.elasticsearch.cluster.routing.RecoverySource.PeerRecoverySource;
import org.elasticsearch.cluster.routing.allocation.allocator.BalancedShardsAllocator;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.common.io.stream.Writeable;
import org.elasticsearch.core.Nullable;
import org.elasticsearch.index.Index;
import org.elasticsearch.index.shard.ShardId;
import org.elasticsearch.xcontent.ToXContentObject;
import org.elasticsearch.xcontent.XContentBuilder;
import java.io.IOException;
import java.util.Collections;
import java.util.List;
import java.util.Objects;
/**
* {@link ShardRouting} immutably encapsulates information about shard
* indexRoutings like id, state, version, etc.
*/
public final class ShardRouting implements Writeable, ToXContentObject {
/**
* Used if shard size is not available
*/
public static final long UNAVAILABLE_EXPECTED_SHARD_SIZE = -1;
private final ShardId shardId;
private final String currentNodeId;
private final String relocatingNodeId;
private final boolean primary;
private final ShardRoutingState state;
private final RecoverySource recoverySource;
private final UnassignedInfo unassignedInfo;
private final AllocationId allocationId;
private final transient List asList;
private final long expectedShardSize;
@Nullable
private final ShardRouting targetRelocatingShard;
/**
* A constructor to internally create shard routing instances, note, the internal flag should only be set to true
* by either this class or tests. Visible for testing.
*/
ShardRouting(
ShardId shardId,
String currentNodeId,
String relocatingNodeId,
boolean primary,
ShardRoutingState state,
RecoverySource recoverySource,
UnassignedInfo unassignedInfo,
AllocationId allocationId,
long expectedShardSize
) {
this.shardId = shardId;
this.currentNodeId = currentNodeId;
this.relocatingNodeId = relocatingNodeId;
this.primary = primary;
this.state = state;
this.recoverySource = recoverySource;
this.unassignedInfo = unassignedInfo;
this.allocationId = allocationId;
this.expectedShardSize = expectedShardSize;
this.targetRelocatingShard = initializeTargetRelocatingShard();
this.asList = Collections.singletonList(this);
assert expectedShardSize == UNAVAILABLE_EXPECTED_SHARD_SIZE
|| state == ShardRoutingState.INITIALIZING
|| state == ShardRoutingState.RELOCATING : expectedShardSize + " state: " + state;
assert expectedShardSize >= 0 || state != ShardRoutingState.INITIALIZING || state != ShardRoutingState.RELOCATING
: expectedShardSize + " state: " + state;
assert (state == ShardRoutingState.UNASSIGNED && unassignedInfo == null) == false : "unassigned shard must be created with meta";
assert (state == ShardRoutingState.UNASSIGNED || state == ShardRoutingState.INITIALIZING) == (recoverySource != null)
: "recovery source only available on unassigned or initializing shard but was " + state;
assert recoverySource == null || recoverySource == PeerRecoverySource.INSTANCE || primary
: "replica shards always recover from primary";
assert (currentNodeId == null) == (state == ShardRoutingState.UNASSIGNED)
: "unassigned shard must not be assigned to a node " + this;
}
@Nullable
private ShardRouting initializeTargetRelocatingShard() {
if (state == ShardRoutingState.RELOCATING) {
return new ShardRouting(
shardId,
relocatingNodeId,
currentNodeId,
primary,
ShardRoutingState.INITIALIZING,
PeerRecoverySource.INSTANCE,
unassignedInfo,
AllocationId.newTargetRelocation(allocationId),
expectedShardSize
);
} else {
return null;
}
}
/**
* Creates a new unassigned shard.
*/
public static ShardRouting newUnassigned(
ShardId shardId,
boolean primary,
RecoverySource recoverySource,
UnassignedInfo unassignedInfo
) {
return new ShardRouting(
shardId,
null,
null,
primary,
ShardRoutingState.UNASSIGNED,
recoverySource,
unassignedInfo,
null,
UNAVAILABLE_EXPECTED_SHARD_SIZE
);
}
public Index index() {
return shardId.getIndex();
}
/**
* The index name.
*/
public String getIndexName() {
return shardId.getIndexName();
}
/**
* The shard id.
*/
public int id() {
return shardId.id();
}
/**
* The shard id.
*/
public int getId() {
return id();
}
/**
* The shard is unassigned (not allocated to any node).
*/
public boolean unassigned() {
return state == ShardRoutingState.UNASSIGNED;
}
/**
* The shard is initializing (usually recovering either from peer shard
* or from gateway).
*/
public boolean initializing() {
return state == ShardRoutingState.INITIALIZING;
}
/**
* Returns true iff the this shard is currently
* {@link ShardRoutingState#STARTED started} or
* {@link ShardRoutingState#RELOCATING relocating} to another node.
* Otherwise false
*/
public boolean active() {
return started() || relocating();
}
/**
* The shard is in started mode.
*/
public boolean started() {
return state == ShardRoutingState.STARTED;
}
/**
* Returns true iff the this shard is currently relocating to
* another node. Otherwise false
*
* @see ShardRoutingState#RELOCATING
*/
public boolean relocating() {
return state == ShardRoutingState.RELOCATING;
}
/**
* Returns true iff this shard is assigned to a node ie. not
* {@link ShardRoutingState#UNASSIGNED unassigned}. Otherwise false
*/
public boolean assignedToNode() {
return currentNodeId != null;
}
/**
* The current node id the shard is allocated on.
*/
public String currentNodeId() {
return this.currentNodeId;
}
/**
* The relocating node id the shard is either relocating to or relocating from.
*/
public String relocatingNodeId() {
return this.relocatingNodeId;
}
/**
* Returns a shard routing representing the target shard.
* The target shard routing will be the INITIALIZING state and have relocatingNodeId set to the
* source node.
*/
public ShardRouting getTargetRelocatingShard() {
assert relocating();
return targetRelocatingShard;
}
/**
* Additional metadata on why the shard is/was unassigned. The metadata is kept around
* until the shard moves to STARTED.
*/
@Nullable
public UnassignedInfo unassignedInfo() {
return unassignedInfo;
}
/**
* An id that uniquely identifies an allocation.
*/
@Nullable
public AllocationId allocationId() {
return this.allocationId;
}
/**
* Returns true iff this shard is a primary.
*/
public boolean primary() {
return this.primary;
}
/**
* The shard state.
*/
public ShardRoutingState state() {
return this.state;
}
/**
* The shard id.
*/
public ShardId shardId() {
return shardId;
}
/**
* A shard iterator with just this shard in it.
*/
public ShardIterator shardsIt() {
return new PlainShardIterator(shardId, asList);
}
public ShardRouting(ShardId shardId, StreamInput in) throws IOException {
this.shardId = shardId;
currentNodeId = in.readOptionalString();
relocatingNodeId = in.readOptionalString();
primary = in.readBoolean();
state = ShardRoutingState.fromValue(in.readByte());
if (state == ShardRoutingState.UNASSIGNED || state == ShardRoutingState.INITIALIZING) {
recoverySource = RecoverySource.readFrom(in);
} else {
recoverySource = null;
}
unassignedInfo = in.readOptionalWriteable(UnassignedInfo::new);
allocationId = in.readOptionalWriteable(AllocationId::new);
final long shardSize;
if (state == ShardRoutingState.RELOCATING || state == ShardRoutingState.INITIALIZING) {
shardSize = in.readLong();
} else {
shardSize = UNAVAILABLE_EXPECTED_SHARD_SIZE;
}
expectedShardSize = shardSize;
asList = Collections.singletonList(this);
targetRelocatingShard = initializeTargetRelocatingShard();
}
public ShardRouting(StreamInput in) throws IOException {
this(new ShardId(in), in);
}
/**
* Writes shard information to {@link StreamOutput} without writing index name and shard id
*
* @param out {@link StreamOutput} to write shard information to
* @throws IOException if something happens during write
*/
public void writeToThin(StreamOutput out) throws IOException {
out.writeOptionalString(currentNodeId);
out.writeOptionalString(relocatingNodeId);
out.writeBoolean(primary);
out.writeByte(state.value());
if (state == ShardRoutingState.UNASSIGNED || state == ShardRoutingState.INITIALIZING) {
recoverySource.writeTo(out);
}
out.writeOptionalWriteable(unassignedInfo);
out.writeOptionalWriteable(allocationId);
if (state == ShardRoutingState.RELOCATING || state == ShardRoutingState.INITIALIZING) {
out.writeLong(expectedShardSize);
}
}
@Override
public void writeTo(StreamOutput out) throws IOException {
shardId.writeTo(out);
writeToThin(out);
}
public ShardRouting updateUnassigned(UnassignedInfo unassignedInfo, RecoverySource recoverySource) {
assert this.unassignedInfo != null : "can only update unassign info if they are already set";
assert this.unassignedInfo.isDelayed() || (unassignedInfo.isDelayed() == false) : "cannot transition from non-delayed to delayed";
return new ShardRouting(
shardId,
currentNodeId,
relocatingNodeId,
primary,
state,
recoverySource,
unassignedInfo,
allocationId,
expectedShardSize
);
}
/**
* Moves the shard to unassigned state.
*/
public ShardRouting moveToUnassigned(UnassignedInfo unassignedInfo) {
assert state != ShardRoutingState.UNASSIGNED : this;
final RecoverySource recoverySource;
if (active()) {
if (primary()) {
recoverySource = ExistingStoreRecoverySource.INSTANCE;
} else {
recoverySource = PeerRecoverySource.INSTANCE;
}
} else {
recoverySource = recoverySource();
}
return new ShardRouting(
shardId,
null,
null,
primary,
ShardRoutingState.UNASSIGNED,
recoverySource,
unassignedInfo,
null,
UNAVAILABLE_EXPECTED_SHARD_SIZE
);
}
/**
* Initializes an unassigned shard on a node.
*
* @param existingAllocationId allocation id to use. If null, a fresh allocation id is generated.
*/
public ShardRouting initialize(String nodeId, @Nullable String existingAllocationId, long expectedShardSize) {
assert state == ShardRoutingState.UNASSIGNED : this;
assert relocatingNodeId == null : this;
final AllocationId allocationId;
if (existingAllocationId == null) {
allocationId = AllocationId.newInitializing();
} else {
allocationId = AllocationId.newInitializing(existingAllocationId);
}
return new ShardRouting(
shardId,
nodeId,
null,
primary,
ShardRoutingState.INITIALIZING,
recoverySource,
unassignedInfo,
allocationId,
expectedShardSize
);
}
/**
* Relocate the shard to another node.
*
* @param relocatingNodeId id of the node to relocate the shard
*/
public ShardRouting relocate(String relocatingNodeId, long expectedShardSize) {
assert state == ShardRoutingState.STARTED : "current shard has to be started in order to be relocated " + this;
return new ShardRouting(
shardId,
currentNodeId,
relocatingNodeId,
primary,
ShardRoutingState.RELOCATING,
recoverySource,
null,
AllocationId.newRelocation(allocationId),
expectedShardSize
);
}
/**
* Cancel relocation of a shard. The shards state must be set
* to RELOCATING.
*/
public ShardRouting cancelRelocation() {
assert state == ShardRoutingState.RELOCATING : this;
assert assignedToNode() : this;
assert relocatingNodeId != null : this;
return new ShardRouting(
shardId,
currentNodeId,
null,
primary,
ShardRoutingState.STARTED,
recoverySource,
null,
AllocationId.cancelRelocation(allocationId),
UNAVAILABLE_EXPECTED_SHARD_SIZE
);
}
/**
* Removes relocation source of a non-primary shard. The shard state must be INITIALIZING.
* This allows the non-primary shard to continue recovery from the primary even though its non-primary
* relocation source has failed.
*/
public ShardRouting removeRelocationSource() {
assert primary == false : this;
assert state == ShardRoutingState.INITIALIZING : this;
assert assignedToNode() : this;
assert relocatingNodeId != null : this;
return new ShardRouting(
shardId,
currentNodeId,
null,
primary,
state,
recoverySource,
unassignedInfo,
AllocationId.finishRelocation(allocationId),
expectedShardSize
);
}
/**
* Reinitializes a replica shard, giving it a fresh allocation id
*/
public ShardRouting reinitializeReplicaShard() {
assert state == ShardRoutingState.INITIALIZING : this;
assert primary == false : this;
assert isRelocationTarget() == false : this;
return new ShardRouting(
shardId,
currentNodeId,
null,
primary,
ShardRoutingState.INITIALIZING,
recoverySource,
unassignedInfo,
AllocationId.newInitializing(),
expectedShardSize
);
}
/**
* Set the shards state to STARTED. The shards state must be
* INITIALIZING or RELOCATING. Any relocation will be
* canceled.
*/
public ShardRouting moveToStarted() {
assert state == ShardRoutingState.INITIALIZING : "expected an initializing shard " + this;
AllocationId allocationId = this.allocationId;
if (allocationId.getRelocationId() != null) {
// relocation target
allocationId = AllocationId.finishRelocation(allocationId);
}
return new ShardRouting(
shardId,
currentNodeId,
null,
primary,
ShardRoutingState.STARTED,
null,
null,
allocationId,
UNAVAILABLE_EXPECTED_SHARD_SIZE
);
}
/**
* Make the active shard primary unless it's not primary
*
* @throws IllegalShardRoutingStateException if shard is already a primary
*/
public ShardRouting moveActiveReplicaToPrimary() {
assert active() : "expected an active shard " + this;
if (primary) {
throw new IllegalShardRoutingStateException(this, "Already primary, can't move to primary");
}
return new ShardRouting(
shardId,
currentNodeId,
relocatingNodeId,
true,
state,
recoverySource,
unassignedInfo,
allocationId,
expectedShardSize
);
}
/**
* Set the unassigned primary shard to non-primary
*
* @throws IllegalShardRoutingStateException if shard is already a replica
*/
public ShardRouting moveUnassignedFromPrimary() {
assert state == ShardRoutingState.UNASSIGNED : "expected an unassigned shard " + this;
if (primary == false) {
throw new IllegalShardRoutingStateException(this, "Not primary, can't move to replica");
}
return new ShardRouting(
shardId,
currentNodeId,
relocatingNodeId,
false,
state,
PeerRecoverySource.INSTANCE,
unassignedInfo,
allocationId,
expectedShardSize
);
}
/**
* returns true if this routing has the same allocation ID as another.
*
* Note: if both shard routing has a null as their {@link #allocationId()}, this method returns false as the routing describe
* no allocation at all..
**/
public boolean isSameAllocation(ShardRouting other) {
boolean b = this.allocationId != null && other.allocationId != null && this.allocationId.getId().equals(other.allocationId.getId());
assert b == false || this.currentNodeId.equals(other.currentNodeId)
: "ShardRoutings have the same allocation id but not the same node. This [" + this + "], other [" + other + "]";
return b;
}
/**
* Returns true if this shard is a relocation target for another shard
* (i.e., was created with {@link #initializeTargetRelocatingShard()}
*/
public boolean isRelocationTarget() {
return state == ShardRoutingState.INITIALIZING && relocatingNodeId != null;
}
/** returns true if the routing is the relocation target of the given routing */
public boolean isRelocationTargetOf(ShardRouting other) {
boolean b = this.allocationId != null
&& other.allocationId != null
&& this.state == ShardRoutingState.INITIALIZING
&& this.allocationId.getId().equals(other.allocationId.getRelocationId());
assert b == false || other.state == ShardRoutingState.RELOCATING
: "ShardRouting is a relocation target but the source shard state isn't relocating. This [" + this + "], other [" + other + "]";
assert b == false || other.allocationId.getId().equals(this.allocationId.getRelocationId())
: "ShardRouting is a relocation target but the source id isn't equal to source's allocationId.getRelocationId."
+ " This ["
+ this
+ "], other ["
+ other
+ "]";
assert b == false || other.currentNodeId().equals(this.relocatingNodeId)
: "ShardRouting is a relocation target but source current node id isn't equal to target relocating node."
+ " This ["
+ this
+ "], other ["
+ other
+ "]";
assert b == false || this.currentNodeId().equals(other.relocatingNodeId)
: "ShardRouting is a relocation target but current node id isn't equal to source relocating node."
+ " This ["
+ this
+ "], other ["
+ other
+ "]";
assert b == false || this.shardId.equals(other.shardId)
: "ShardRouting is a relocation target but both indexRoutings are not of the same shard id."
+ " This ["
+ this
+ "], other ["
+ other
+ "]";
assert b == false || this.primary == other.primary
: "ShardRouting is a relocation target but primary flag is different." + " This [" + this + "], target [" + other + "]";
return b;
}
/** returns true if the routing is the relocation source for the given routing */
public boolean isRelocationSourceOf(ShardRouting other) {
boolean b = this.allocationId != null
&& other.allocationId != null
&& other.state == ShardRoutingState.INITIALIZING
&& other.allocationId.getId().equals(this.allocationId.getRelocationId());
assert b == false || this.state == ShardRoutingState.RELOCATING
: "ShardRouting is a relocation source but shard state isn't relocating. This [" + this + "], other [" + other + "]";
assert b == false || this.allocationId.getId().equals(other.allocationId.getRelocationId())
: "ShardRouting is a relocation source but the allocation id isn't equal to other.allocationId.getRelocationId."
+ " This ["
+ this
+ "], other ["
+ other
+ "]";
assert b == false || this.currentNodeId().equals(other.relocatingNodeId)
: "ShardRouting is a relocation source but current node isn't equal to other's relocating node."
+ " This ["
+ this
+ "], other ["
+ other
+ "]";
assert b == false || other.currentNodeId().equals(this.relocatingNodeId)
: "ShardRouting is a relocation source but relocating node isn't equal to other's current node."
+ " This ["
+ this
+ "], other ["
+ other
+ "]";
assert b == false || this.shardId.equals(other.shardId)
: "ShardRouting is a relocation source but both indexRoutings are not of the same shard."
+ " This ["
+ this
+ "], target ["
+ other
+ "]";
assert b == false || this.primary == other.primary
: "ShardRouting is a relocation source but primary flag is different. This [" + this + "], target [" + other + "]";
return b;
}
/** returns true if the current routing is identical to the other routing in all but meta fields, i.e., unassigned info */
public boolean equalsIgnoringMetadata(ShardRouting other) {
return primary == other.primary
&& Objects.equals(shardId, other.shardId)
&& Objects.equals(currentNodeId, other.currentNodeId)
&& Objects.equals(relocatingNodeId, other.relocatingNodeId)
&& Objects.equals(allocationId, other.allocationId)
&& state == other.state
&& Objects.equals(recoverySource, other.recoverySource);
}
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (o == null || getClass() != o.getClass()) {
return false;
}
ShardRouting that = (ShardRouting) o;
return Objects.equals(unassignedInfo, that.unassignedInfo) && equalsIgnoringMetadata(that);
}
/**
* Cache hash code in the same way as {@link String#hashCode()}) using racy single-check idiom
* as it is mainly used in single-threaded code ({@link BalancedShardsAllocator}).
*/
private int hashCode; // default to 0
@Override
public int hashCode() {
int h = hashCode;
if (h == 0) {
h = shardId.hashCode();
h = 31 * h + (currentNodeId != null ? currentNodeId.hashCode() : 0);
h = 31 * h + (relocatingNodeId != null ? relocatingNodeId.hashCode() : 0);
h = 31 * h + (primary ? 1 : 0);
h = 31 * h + (state != null ? state.hashCode() : 0);
h = 31 * h + (recoverySource != null ? recoverySource.hashCode() : 0);
h = 31 * h + (allocationId != null ? allocationId.hashCode() : 0);
h = 31 * h + (unassignedInfo != null ? unassignedInfo.hashCode() : 0);
hashCode = h;
}
return h;
}
@Override
public String toString() {
return shortSummary();
}
/**
* A short description of the shard.
*/
public String shortSummary() {
StringBuilder sb = new StringBuilder();
sb.append('[').append(shardId.getIndexName()).append(']').append('[').append(shardId.getId()).append(']');
sb.append(", node[").append(currentNodeId).append("], ");
if (relocatingNodeId != null) {
sb.append("relocating [").append(relocatingNodeId).append("], ");
}
if (primary) {
sb.append("[P]");
} else {
sb.append("[R]");
}
if (recoverySource != null) {
sb.append(", recovery_source[").append(recoverySource).append("]");
}
sb.append(", s[").append(state).append("]");
if (allocationId != null) {
sb.append(", a").append(allocationId);
}
if (this.unassignedInfo != null) {
sb.append(", ").append(unassignedInfo.toString());
}
if (expectedShardSize != UNAVAILABLE_EXPECTED_SHARD_SIZE) {
sb.append(", expected_shard_size[").append(expectedShardSize).append("]");
}
return sb.toString();
}
@Override
public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
builder.startObject()
.field("state", state())
.field("primary", primary())
.field("node", currentNodeId())
.field("relocating_node", relocatingNodeId())
.field("shard", id())
.field("index", getIndexName());
if (expectedShardSize != UNAVAILABLE_EXPECTED_SHARD_SIZE) {
builder.field("expected_shard_size_in_bytes", expectedShardSize);
}
if (recoverySource != null) {
builder.field("recovery_source", recoverySource);
}
if (allocationId != null) {
builder.field("allocation_id");
allocationId.toXContent(builder, params);
}
if (unassignedInfo != null) {
unassignedInfo.toXContent(builder, params);
}
return builder.endObject();
}
/**
* Returns the expected shard size for {@link ShardRoutingState#RELOCATING} and {@link ShardRoutingState#INITIALIZING}
* shards. If it's size is not available {@value #UNAVAILABLE_EXPECTED_SHARD_SIZE} will be returned.
*/
public long getExpectedShardSize() {
return expectedShardSize;
}
/**
* Returns recovery source for the given shard. Replica shards always recover from the primary {@link PeerRecoverySource}.
*
* @return recovery source or null if shard is {@link #active()}
*/
@Nullable
public RecoverySource recoverySource() {
return recoverySource;
}
}