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Reuse previous indices lookup when possible (#79004)
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In cases when indices, aliases and data streams aren't modified then
the indices lookup can be reused.

For example in:
* The IndexMetadataUpdater#applyChanges(...) method builds a new metadata
instance, but only primary term or insync allocations may be updated.
No new indices, aliases or data streams are added, so re-building indices
lookup is not necessary.
* MasterService#patchVersions

Additionally the logic that checks when indices lookup can be reused,
this logic also checks the hidden and system flags of indices/datastreams.

In clusters with many indices the cost of building indices lookup is
non-neglectable and should be avoided in this case.

Closes #78980
Partially addresses to #77888
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@martijnvg
martijnvg authored Oct 26, 2021
1 parent 5ee9bde commit bada1ba
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Showing 12 changed files with 223 additions and 14 deletions.
49 changes: 49 additions & 0 deletions server/src/main/java/org/elasticsearch/cluster/metadata/IndexAbstraction.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -179,6 +179,23 @@ public boolean isSystem() {
public List<String> getAliases() {
return aliases;
}

@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
ConcreteIndex that = (ConcreteIndex) o;
return isHidden == that.isHidden &&
isSystem == that.isSystem &&
concreteIndexName.equals(that.concreteIndexName) &&
Objects.equals(aliases, that.aliases) &&
Objects.equals(dataStream, that.dataStream);
}

@Override
public int hashCode() {
return Objects.hash(concreteIndexName, isHidden, isSystem, aliases, dataStream);
}
}

/**
Expand Down Expand Up @@ -322,6 +339,24 @@ private void validateAliasProperties(List<IndexMetadata> referenceIndexMetadatas
private boolean isNonEmpty(List<IndexMetadata> idxMetas) {
return (Objects.isNull(idxMetas) || idxMetas.isEmpty()) == false;
}

@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
Alias alias = (Alias) o;
return isHidden == alias.isHidden &&
isSystem == alias.isSystem &&
dataStreamAlias == alias.dataStreamAlias &&
aliasName.equals(alias.aliasName) &&
referenceIndexMetadatas.equals(alias.referenceIndexMetadatas) &&
Objects.equals(writeIndex, alias.writeIndex);
}

@Override
public int hashCode() {
return Objects.hash(aliasName, referenceIndexMetadatas, writeIndex, isHidden, isSystem, dataStreamAlias);
}
}

class DataStream implements IndexAbstraction {
Expand Down Expand Up @@ -383,6 +418,20 @@ public List<String> getAliases() {
public org.elasticsearch.cluster.metadata.DataStream getDataStream() {
return dataStream;
}

@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
DataStream that = (DataStream) o;
return dataStream.equals(that.dataStream) &&
Objects.equals(referencedByDataStreamAliases, that.referencedByDataStreamAliases);
}

@Override
public int hashCode() {
return Objects.hash(dataStream, referencedByDataStreamAliases);
}
}

}
69 changes: 63 additions & 6 deletions server/src/main/java/org/elasticsearch/cluster/metadata/Metadata.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1038,15 +1038,18 @@ public static class Builder {
private final ImmutableOpenMap.Builder<String, IndexTemplateMetadata> templates;
private final ImmutableOpenMap.Builder<String, Custom> customs;

private SortedMap<String, IndexAbstraction> previousIndicesLookup;

public Builder() {
clusterUUID = UNKNOWN_CLUSTER_UUID;
indices = ImmutableOpenMap.builder();
templates = ImmutableOpenMap.builder();
customs = ImmutableOpenMap.builder();
indexGraveyard(IndexGraveyard.builder().build()); // create new empty index graveyard to initialize
previousIndicesLookup = null;
}

public Builder(Metadata metadata) {
Builder(Metadata metadata) {
this.clusterUUID = metadata.clusterUUID;
this.clusterUUIDCommitted = metadata.clusterUUIDCommitted;
this.coordinationMetadata = metadata.coordinationMetadata;
Expand All @@ -1057,13 +1060,17 @@ public Builder(Metadata metadata) {
this.indices = ImmutableOpenMap.builder(metadata.indices);
this.templates = ImmutableOpenMap.builder(metadata.templates);
this.customs = ImmutableOpenMap.builder(metadata.customs);
previousIndicesLookup = metadata.getIndicesLookup();
}

public Builder put(IndexMetadata.Builder indexMetadataBuilder) {
// we know its a new one, increment the version and store
indexMetadataBuilder.version(indexMetadataBuilder.version() + 1);
IndexMetadata indexMetadata = indexMetadataBuilder.build();
indices.put(indexMetadata.getIndex().getName(), indexMetadata);
IndexMetadata previous = indices.put(indexMetadata.getIndex().getName(), indexMetadata);
if (unsetPreviousIndicesLookup(previous, indexMetadata)) {
previousIndicesLookup = null;
}
return this;
}

Expand All @@ -1075,10 +1082,37 @@ public Builder put(IndexMetadata indexMetadata, boolean incrementVersion) {
if (incrementVersion) {
indexMetadata = IndexMetadata.builder(indexMetadata).version(indexMetadata.getVersion() + 1).build();
}
indices.put(indexMetadata.getIndex().getName(), indexMetadata);
IndexMetadata previous = indices.put(indexMetadata.getIndex().getName(), indexMetadata);
if (unsetPreviousIndicesLookup(previous, indexMetadata)) {
previousIndicesLookup = null;
}
return this;
}

boolean unsetPreviousIndicesLookup(IndexMetadata previous, IndexMetadata current) {
if (previous == null) {
return true;
}

if (previous.getAliases().equals(current.getAliases()) == false) {
return true;
}

if (previous.isHidden() != current.isHidden()) {
return true;
}

if (previous.isSystem() != current.isSystem()) {
return true;
}

if (previous.getState() != current.getState()) {
return true;
}

return false;
}

public IndexMetadata get(String index) {
return indices.get(index);
}
Expand All @@ -1097,16 +1131,22 @@ public IndexMetadata getSafe(Index index) {
}

public Builder remove(String index) {
previousIndicesLookup = null;

indices.remove(index);
return this;
}

public Builder removeAllIndices() {
previousIndicesLookup = null;

indices.clear();
return this;
}

public Builder indices(ImmutableOpenMap<String, IndexMetadata> indices) {
previousIndicesLookup = null;

this.indices.putAll(indices);
return this;
}
Expand Down Expand Up @@ -1187,6 +1227,8 @@ public Builder removeIndexTemplate(String name) {
}

public DataStream dataStream(String dataStreamName) {
previousIndicesLookup = null;

DataStreamMetadata dataStreamMetadata = (DataStreamMetadata) customs.get(DataStreamMetadata.TYPE);
if (dataStreamMetadata != null) {
return dataStreamMetadata.dataStreams().get(dataStreamName);
Expand All @@ -1196,11 +1238,15 @@ public DataStream dataStream(String dataStreamName) {
}

public Builder dataStreams(Map<String, DataStream> dataStreams, Map<String, DataStreamAlias> dataStreamAliases) {
previousIndicesLookup = null;

this.customs.put(DataStreamMetadata.TYPE, new DataStreamMetadata(dataStreams, dataStreamAliases));
return this;
}

public Builder put(DataStream dataStream) {
previousIndicesLookup = null;

Objects.requireNonNull(dataStream, "it is invalid to add a null data stream");
Map<String, DataStream> existingDataStreams =
Optional.ofNullable((DataStreamMetadata) this.customs.get(DataStreamMetadata.TYPE))
Expand All @@ -1217,6 +1263,8 @@ public Builder put(DataStream dataStream) {
}

public boolean put(String aliasName, String dataStream, Boolean isWriteDataStream, String filter) {
previousIndicesLookup = null;

Map<String, DataStream> existingDataStream =
Optional.ofNullable((DataStreamMetadata) this.customs.get(DataStreamMetadata.TYPE))
.map(dsmd -> new HashMap<>(dsmd.dataStreams()))
Expand Down Expand Up @@ -1255,6 +1303,8 @@ public boolean put(String aliasName, String dataStream, Boolean isWriteDataStrea
}

public Builder removeDataStream(String name) {
previousIndicesLookup = null;

Map<String, DataStream> existingDataStreams =
Optional.ofNullable((DataStreamMetadata) this.customs.get(DataStreamMetadata.TYPE))
.map(dsmd -> new HashMap<>(dsmd.dataStreams()))
Expand Down Expand Up @@ -1291,6 +1341,8 @@ public Builder removeDataStream(String name) {
}

public boolean removeDataStreamAlias(String aliasName, String dataStreamName, boolean mustExist) {
previousIndicesLookup = null;

Map<String, DataStreamAlias> dataStreamAliases =
Optional.ofNullable((DataStreamMetadata) this.customs.get(DataStreamMetadata.TYPE))
.map(dsmd -> new HashMap<>(dsmd.getDataStreamAliases()))
Expand Down Expand Up @@ -1538,10 +1590,15 @@ public Metadata build(boolean builtIndicesLookupEagerly) {
ImmutableOpenMap<String, IndexMetadata> indices = this.indices.build();

SortedMap<String, IndexAbstraction> indicesLookup;
if (builtIndicesLookupEagerly) {
indicesLookup = Collections.unmodifiableSortedMap(buildIndicesLookup(dataStreamMetadata, indices));
if (previousIndicesLookup != null) {
assert previousIndicesLookup.equals(buildIndicesLookup(dataStreamMetadata, indices));
indicesLookup = previousIndicesLookup;
} else {
indicesLookup = null;
if (builtIndicesLookupEagerly) {
indicesLookup = Collections.unmodifiableSortedMap(buildIndicesLookup(dataStreamMetadata, indices));
} else {
indicesLookup = null;
}
}


Expand Down
4 changes: 3 additions & 1 deletion server/src/main/java/org/elasticsearch/cluster/routing/allocation/IndexMetadataUpdater.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -121,7 +121,9 @@ public Metadata applyChanges(Metadata oldMetadata, RoutingTable newRoutingTable)
}

if (metadataBuilder != null) {
return metadataBuilder.build();
Metadata newMetadata = metadataBuilder.build();
assert oldMetadata.getIndicesLookup() == newMetadata.getIndicesLookup();
return newMetadata;
} else {
return oldMetadata;
}
Expand Down
2 changes: 2 additions & 0 deletions server/src/main/java/org/elasticsearch/cluster/service/MasterService.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -368,6 +368,7 @@ private ClusterState patchVersions(ClusterState previousClusterState, ClusterTas

if (previousClusterState != newClusterState) {
// only the master controls the version numbers
final var previousIndicesLookup = newClusterState.metadata().getIndicesLookup();
Builder builder = incrementVersion(newClusterState);
if (previousClusterState.routingTable() != newClusterState.routingTable()) {
builder.routingTable(RoutingTable.builder(newClusterState.routingTable())
Expand All @@ -378,6 +379,7 @@ private ClusterState patchVersions(ClusterState previousClusterState, ClusterTas
}

newClusterState = builder.build();
assert previousIndicesLookup == newClusterState.metadata().getIndicesLookup();
}

return newClusterState;
Expand Down
2 changes: 1 addition & 1 deletion server/src/test/java/org/elasticsearch/cluster/ClusterChangedEventTests.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -354,7 +354,7 @@ private static ClusterState createNonInitializedState(final int numNodes, final
private static ClusterState nextState(final ClusterState previousState, List<TestCustomMetadata> customMetadataList) {
final ClusterState.Builder builder = ClusterState.builder(previousState);
builder.stateUUID(UUIDs.randomBase64UUID());
Metadata.Builder metadataBuilder = new Metadata.Builder(previousState.metadata());
Metadata.Builder metadataBuilder = Metadata.builder(previousState.metadata());
for (ObjectObjectCursor<String, Metadata.Custom> customMetadata : previousState.metadata().customs()) {
if (customMetadata.value instanceof TestCustomMetadata) {
metadataBuilder.removeCustom(customMetadata.key);
Expand Down
99 changes: 99 additions & 0 deletions server/src/test/java/org/elasticsearch/cluster/metadata/MetadataTests.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,7 @@
import org.elasticsearch.common.settings.Setting;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.util.set.Sets;
import org.elasticsearch.index.IndexSettings;
import org.elasticsearch.xcontent.XContentBuilder;
import org.elasticsearch.common.xcontent.XContentHelper;
import org.elasticsearch.xcontent.XContentParser;
Expand Down Expand Up @@ -57,8 +58,10 @@
import static org.hamcrest.Matchers.equalTo;
import static org.hamcrest.Matchers.greaterThanOrEqualTo;
import static org.hamcrest.Matchers.is;
import static org.hamcrest.Matchers.not;
import static org.hamcrest.Matchers.notNullValue;
import static org.hamcrest.Matchers.nullValue;
import static org.hamcrest.Matchers.sameInstance;
import static org.hamcrest.Matchers.startsWith;

public class MetadataTests extends ESTestCase {
Expand Down Expand Up @@ -1520,6 +1523,102 @@ public void testDataStreamWriteRemoveDataStream() {
assertThat(metadata.dataStreamAliases().get("logs-postgres").getDataStreams(), containsInAnyOrder("logs-postgres-replicated"));
}

public void testReuseIndicesLookup() {
String indexName = "my-index";
String aliasName = "my-alias";
String dataStreamName = "logs-mysql-prod";
String dataStreamAliasName = "logs-mysql";
Metadata previous = Metadata.builder().build();

// Things that should change indices lookup
{
Metadata.Builder builder = Metadata.builder(previous);
IndexMetadata idx = DataStreamTestHelper.createFirstBackingIndex(dataStreamName).build();
builder.put(idx, true);
DataStream dataStream = new DataStream(dataStreamName, new DataStream.TimestampField("@timestamp"), List.of(idx.getIndex()));
builder.put(dataStream);
Metadata metadata = builder.build();
assertThat(previous.getIndicesLookup(), not(sameInstance(metadata.getIndicesLookup())));
previous = metadata;
}
{
Metadata.Builder builder = Metadata.builder(previous);
builder.put(dataStreamAliasName, dataStreamName, false, null);
Metadata metadata = builder.build();
assertThat(previous.getIndicesLookup(), not(sameInstance(metadata.getIndicesLookup())));
previous = metadata;
}
{
Metadata.Builder builder = Metadata.builder(previous);
builder.put(dataStreamAliasName, dataStreamName, true, null);
Metadata metadata = builder.build();
assertThat(previous.getIndicesLookup(), not(sameInstance(metadata.getIndicesLookup())));
previous = metadata;
}
{
Metadata.Builder builder = Metadata.builder(previous);
builder.put(IndexMetadata.builder(indexName)
.settings(settings(Version.CURRENT)).creationDate(randomNonNegativeLong())
.numberOfShards(1).numberOfReplicas(0));
Metadata metadata = builder.build();
assertThat(previous.getIndicesLookup(), not(sameInstance(metadata.getIndicesLookup())));
previous = metadata;
}
{
Metadata.Builder builder = Metadata.builder(previous);
IndexMetadata.Builder imBuilder = IndexMetadata.builder(builder.get(indexName));
imBuilder.putAlias(AliasMetadata.builder(aliasName).build());
builder.put(imBuilder);
Metadata metadata = builder.build();
assertThat(previous.getIndicesLookup(), not(sameInstance(metadata.getIndicesLookup())));
previous = metadata;
}
{
Metadata.Builder builder = Metadata.builder(previous);
IndexMetadata.Builder imBuilder = IndexMetadata.builder(builder.get(indexName));
imBuilder.putAlias(AliasMetadata.builder(aliasName).writeIndex(true).build());
builder.put(imBuilder);
Metadata metadata = builder.build();
assertThat(previous.getIndicesLookup(), not(sameInstance(metadata.getIndicesLookup())));
previous = metadata;
}
{
Metadata.Builder builder = Metadata.builder(previous);
IndexMetadata.Builder imBuilder = IndexMetadata.builder(builder.get(indexName));
Settings.Builder sBuilder = Settings.builder()
.put(builder.get(indexName).getSettings())
.put(IndexMetadata.INDEX_HIDDEN_SETTING.getKey(), true);
imBuilder.settings(sBuilder.build());
builder.put(imBuilder);
Metadata metadata = builder.build();
assertThat(previous.getIndicesLookup(), not(sameInstance(metadata.getIndicesLookup())));
previous = metadata;
}

// Things that shouldn't change indices lookup
{
Metadata.Builder builder = Metadata.builder(previous);
IndexMetadata.Builder imBuilder = IndexMetadata.builder(builder.get(indexName));
imBuilder.numberOfReplicas(2);
builder.put(imBuilder);
Metadata metadata = builder.build();
assertThat(previous.getIndicesLookup(), sameInstance(metadata.getIndicesLookup()));
previous = metadata;
}
{
Metadata.Builder builder = Metadata.builder(previous);
IndexMetadata.Builder imBuilder = IndexMetadata.builder(builder.get(indexName));
Settings.Builder sBuilder = Settings.builder()
.put(builder.get(indexName).getSettings())
.put(IndexSettings.DEFAULT_FIELD_SETTING.getKey(), "val");
imBuilder.settings(sBuilder.build());
builder.put(imBuilder);
Metadata metadata = builder.build();
assertThat(previous.getIndicesLookup(), sameInstance(metadata.getIndicesLookup()));
previous = metadata;
}
}

public static Metadata randomMetadata() {
return randomMetadata(1);
}
Expand Down
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