OTLP: optimize _tsid creation

server/src/main/java/org/elasticsearch/cluster/routing/TsidBuilder.java

@@ -207,7 +207,6 @@ public TsidBuilder addAll(TsidBuilder other) {
      * @throws IllegalArgumentException if no dimensions have been added
      */
     public MurmurHash3.Hash128 hash() {
-        throwIfEmpty();
         Collections.sort(dimensions);
         murmur3Hasher.reset();
         for (Dimension dim : dimensions) {

server/src/test/java/org/elasticsearch/cluster/routing/TsidBuilderTests.java

@@ -10,6 +10,7 @@
 package org.elasticsearch.cluster.routing;
 
 import org.apache.lucene.util.BytesRef;
+import org.elasticsearch.common.hash.MurmurHash3;
 import org.elasticsearch.test.ESTestCase;
 import org.elasticsearch.xcontent.Text;
 
@@ -115,11 +116,9 @@ public void testAddAllWithNullOrEmpty() {
     }
 
     public void testExceptionWhenNoDimensions() {
-        // Test that exception is thrown when no dimensions are added
         TsidBuilder builder = TsidBuilder.newBuilder();
 
-        IllegalArgumentException hashException = expectThrows(IllegalArgumentException.class, builder::hash);
-        assertTrue(hashException.getMessage().contains("Dimensions are empty"));
+        assertThat(builder.hash(), equalTo(new MurmurHash3.Hash128()));
 
         IllegalArgumentException tsidException = expectThrows(IllegalArgumentException.class, builder::buildTsid);
         assertTrue(tsidException.getMessage().contains("Dimensions are empty"));

x-pack/plugin/otel-data/src/main/java/org/elasticsearch/xpack/oteldata/otlp/OTLPMetricsTransportAction.java

@@ -15,6 +15,7 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import org.apache.lucene.util.BytesRef;
 import org.elasticsearch.ExceptionsHelper;
 import org.elasticsearch.action.ActionListener;
 import org.elasticsearch.action.ActionRequest;
@@ -35,6 +36,7 @@
 import org.elasticsearch.common.io.stream.BytesStreamOutput;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
+import org.elasticsearch.common.util.Maps;
 import org.elasticsearch.injection.guice.Inject;
 import org.elasticsearch.rest.RestStatus;
 import org.elasticsearch.tasks.Task;
@@ -47,6 +49,7 @@
 import org.elasticsearch.xpack.oteldata.otlp.proto.BufferedByteStringAccessor;
 
 import java.io.IOException;
+import java.util.Map;
 
 /**
  * Transport action for handling OpenTelemetry Protocol (OTLP) Metrics requests.
@@ -126,11 +129,13 @@ private void addIndexRequest(
         DataPointGroupingContext.DataPointGroup dataPointGroup
     ) throws IOException {
         try (XContentBuilder xContentBuilder = XContentFactory.cborBuilder(new BytesStreamOutput())) {
-            var dynamicTemplates = metricDocumentBuilder.buildMetricDocument(xContentBuilder, dataPointGroup);
+            Map<String, String> dynamicTemplates = Maps.newHashMapWithExpectedSize(dataPointGroup.dataPoints().size());
+            BytesRef tsid = metricDocumentBuilder.buildMetricDocument(xContentBuilder, dynamicTemplates, dataPointGroup);
             bulkRequestBuilder.add(
                 new IndexRequest(dataPointGroup.targetIndex().index()).opType(DocWriteRequest.OpType.CREATE)
                     .setRequireDataStream(true)
                     .source(xContentBuilder)
+                    .tsid(tsid)
                     .setDynamicTemplates(dynamicTemplates)
             );
         }

x-pack/plugin/otel-data/src/main/java/org/elasticsearch/xpack/oteldata/otlp/datapoint/DataPointGroupingContext.java

@@ -128,7 +128,7 @@ private ResourceGroup getOrCreateResourceGroup(ResourceMetrics resourceMetrics)
         Hash128 resourceHash = resourceTsidBuilder.hash();
         ResourceGroup resourceGroup = resourceGroups.get(resourceHash);
         if (resourceGroup == null) {
-            resourceGroup = new ResourceGroup(resourceMetrics.getResource(), resourceMetrics.getSchemaUrlBytes());
+            resourceGroup = new ResourceGroup(resourceMetrics.getResource(), resourceMetrics.getSchemaUrlBytes(), resourceTsidBuilder);
             resourceGroups.put(resourceHash, resourceGroup);
         }
         return resourceGroup;
@@ -137,20 +137,23 @@ private ResourceGroup getOrCreateResourceGroup(ResourceMetrics resourceMetrics)
     class ResourceGroup {
         private final Resource resource;
         private final ByteString resourceSchemaUrl;
+        private final TsidBuilder resourceTsidBuilder;
         private final Map<Hash128, ScopeGroup> scopes;
 
-        ResourceGroup(Resource resource, ByteString resourceSchemaUrl) {
+        ResourceGroup(Resource resource, ByteString resourceSchemaUrl, TsidBuilder resourceTsidBuilder) {
             this.resource = resource;
             this.resourceSchemaUrl = resourceSchemaUrl;
+            this.resourceTsidBuilder = resourceTsidBuilder;
             this.scopes = new HashMap<>();
         }
 
         public ScopeGroup getOrCreateScope(ScopeMetrics scopeMetrics) {
             TsidBuilder scopeTsidBuilder = ScopeTsidFunnel.forScope(byteStringAccessor, scopeMetrics);
             Hash128 scopeHash = scopeTsidBuilder.hash();
+            scopeTsidBuilder.addAll(resourceTsidBuilder);
             ScopeGroup scopeGroup = scopes.get(scopeHash);
             if (scopeGroup == null) {
-                scopeGroup = new ScopeGroup(this, scopeMetrics.getScope(), scopeMetrics.getSchemaUrlBytes());
+                scopeGroup = new ScopeGroup(this, scopeMetrics.getScope(), scopeMetrics.getSchemaUrlBytes(), scopeTsidBuilder);
                 scopes.put(scopeHash, scopeGroup);
             }
             return scopeGroup;
@@ -169,15 +172,17 @@ class ScopeGroup {
         private final ResourceGroup resourceGroup;
         private final InstrumentationScope scope;
         private final ByteString scopeSchemaUrl;
+        private final TsidBuilder scopeTsidBuilder;
         @Nullable
         private final String receiverName;
         // index -> timestamp -> dataPointGroupHash -> DataPointGroup
         private final Map<TargetIndex, Map<Hash128, Map<Hash128, DataPointGroup>>> dataPointGroupsByIndexAndTimestamp;
 
-        ScopeGroup(ResourceGroup resourceGroup, InstrumentationScope scope, ByteString scopeSchemaUrl) {
+        ScopeGroup(ResourceGroup resourceGroup, InstrumentationScope scope, ByteString scopeSchemaUrl, TsidBuilder scopeTsidBuilder) {
             this.resourceGroup = resourceGroup;
             this.scope = scope;
             this.scopeSchemaUrl = scopeSchemaUrl;
+            this.scopeTsidBuilder = scopeTsidBuilder;
             this.dataPointGroupsByIndexAndTimestamp = new HashMap<>();
             this.receiverName = extractReceiverName(scope);
         }
@@ -216,8 +221,13 @@ public void addDataPoint(DataPoint dataPoint) {
         }
 
         private DataPointGroup getOrCreateDataPointGroup(DataPoint dataPoint) {
-            TsidBuilder dataPointGroupTsidBuilder = DataPointTsidFunnel.forDataPoint(byteStringAccessor, dataPoint);
+            TsidBuilder dataPointGroupTsidBuilder = DataPointTsidFunnel.forDataPoint(
+                byteStringAccessor,
+                dataPoint,
+                scopeTsidBuilder.size()
+            );
             Hash128 dataPointGroupHash = dataPointGroupTsidBuilder.hash();
+            dataPointGroupTsidBuilder.addAll(scopeTsidBuilder);
             // in addition to the fields that go into the _tsid, we also need to group by timestamp and start timestamp
             Hash128 timestamp = new Hash128(dataPoint.getTimestampUnixNano(), dataPoint.getStartTimestampUnixNano());
             TargetIndex targetIndex = TargetIndex.evaluate(
@@ -236,6 +246,7 @@ private DataPointGroup getOrCreateDataPointGroup(DataPoint dataPoint) {
                     resourceGroup.resourceSchemaUrl,
                     scope,
                     scopeSchemaUrl,
+                    dataPointGroupTsidBuilder,
                     dataPoint.getAttributes(),
                     dataPoint.getUnit(),
                     targetIndex
@@ -261,6 +272,7 @@ public static final class DataPointGroup {
         private final ByteString resourceSchemaUrl;
         private final InstrumentationScope scope;
         private final ByteString scopeSchemaUrl;
+        private final TsidBuilder tsidBuilder;
         private final List<KeyValue> dataPointAttributes;
         private final String unit;
         private final Set<String> metricNames = new HashSet<>();
@@ -273,6 +285,7 @@ public DataPointGroup(
             ByteString resourceSchemaUrl,
             InstrumentationScope scope,
             ByteString scopeSchemaUrl,
+            TsidBuilder tsidBuilder,
             List<KeyValue> dataPointAttributes,
             String unit,
             TargetIndex targetIndex
@@ -281,6 +294,7 @@ public DataPointGroup(
             this.resourceSchemaUrl = resourceSchemaUrl;
             this.scope = scope;
             this.scopeSchemaUrl = scopeSchemaUrl;
+            this.tsidBuilder = tsidBuilder;
             this.dataPointAttributes = dataPointAttributes;
             this.unit = unit;
             this.targetIndex = targetIndex;
@@ -334,6 +348,10 @@ public ByteString scopeSchemaUrl() {
             return scopeSchemaUrl;
         }
 
+        public TsidBuilder tsidBuilder() {
+            return tsidBuilder;
+        }
+
         public List<KeyValue> dataPointAttributes() {
             return dataPointAttributes;
         }

x-pack/plugin/otel-data/src/main/java/org/elasticsearch/xpack/oteldata/otlp/docbuilder/MetricDocumentBuilder.java

@@ -14,6 +14,8 @@
 
 import com.google.protobuf.ByteString;
 
+import org.apache.lucene.util.BytesRef;
+import org.elasticsearch.cluster.routing.TsidBuilder;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.hash.BufferedMurmur3Hasher;
 import org.elasticsearch.xcontent.XContentBuilder;
@@ -23,8 +25,8 @@
 import org.elasticsearch.xpack.oteldata.otlp.proto.BufferedByteStringAccessor;
 
 import java.io.IOException;
-import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.concurrent.TimeUnit;
 
 /**
@@ -40,9 +42,11 @@ public MetricDocumentBuilder(BufferedByteStringAccessor byteStringAccessor) {
         this.byteStringAccessor = byteStringAccessor;
     }
 
-    public HashMap<String, String> buildMetricDocument(XContentBuilder builder, DataPointGroupingContext.DataPointGroup dataPointGroup)
-        throws IOException {
-        HashMap<String, String> dynamicTemplates = new HashMap<>();
+    public BytesRef buildMetricDocument(
+        XContentBuilder builder,
+        Map<String, String> dynamicTemplates,
+        DataPointGroupingContext.DataPointGroup dataPointGroup
+    ) throws IOException {
         List<DataPoint> dataPoints = dataPointGroup.dataPoints();
         builder.startObject();
         builder.field("@timestamp", TimeUnit.NANOSECONDS.toMillis(dataPointGroup.getTimestampUnixNano()));
@@ -53,7 +57,8 @@ public HashMap<String, String> buildMetricDocument(XContentBuilder builder, Data
         buildDataStream(builder, dataPointGroup.targetIndex());
         buildScope(builder, dataPointGroup.scopeSchemaUrl(), dataPointGroup.scope());
         buildDataPointAttributes(builder, dataPointGroup.dataPointAttributes(), dataPointGroup.unit());
-        builder.field("_metric_names_hash", dataPointGroup.getMetricNamesHash(hasher));
+        String metricNamesHash = dataPointGroup.getMetricNamesHash(hasher);
+        builder.field("_metric_names_hash", metricNamesHash);
 
         long docCount = 0;
         builder.startObject("metrics");
@@ -75,7 +80,9 @@ public HashMap<String, String> buildMetricDocument(XContentBuilder builder, Data
             builder.field("_doc_count", docCount);
         }
         builder.endObject();
-        return dynamicTemplates;
+        TsidBuilder tsidBuilder = dataPointGroup.tsidBuilder();
+        tsidBuilder.addStringDimension("_metric_names_hash", metricNamesHash);
+        return tsidBuilder.buildTsid();
     }
 
     private void buildResource(Resource resource, ByteString schemaUrl, XContentBuilder builder) throws IOException {

x-pack/plugin/otel-data/src/main/java/org/elasticsearch/xpack/oteldata/otlp/tsid/DataPointTsidFunnel.java

@@ -14,14 +14,17 @@
 
 public class DataPointTsidFunnel implements TsidFunnel<DataPoint> {
 
+    // for "unit" and "_metric_names_hash" that will be added in
+    // MetricDocumentBuilder once the data point group is complete
+    private static final int EXTRA_DIMENSIONS_SIZE = 2;
     private final BufferedByteStringAccessor byteStringAccessor;
 
     private DataPointTsidFunnel(BufferedByteStringAccessor byteStringAccessor) {
         this.byteStringAccessor = byteStringAccessor;
     }
 
-    public static TsidBuilder forDataPoint(BufferedByteStringAccessor byteStringAccessor, DataPoint dataPoint) {
-        TsidBuilder tsidBuilder = new TsidBuilder(dataPoint.getAttributes().size());
+    public static TsidBuilder forDataPoint(BufferedByteStringAccessor byteStringAccessor, DataPoint dataPoint, int scopeTsidBuilderSize) {
+        TsidBuilder tsidBuilder = new TsidBuilder(dataPoint.getAttributes().size() + scopeTsidBuilderSize + EXTRA_DIMENSIONS_SIZE);
         new DataPointTsidFunnel(byteStringAccessor).add(dataPoint, tsidBuilder);
         return tsidBuilder;
     }

x-pack/plugin/otel-data/src/main/java/org/elasticsearch/xpack/oteldata/otlp/tsid/ResourceTsidFunnel.java

@@ -25,7 +25,7 @@ public ResourceTsidFunnel(BufferedByteStringAccessor byteStringAccessor) {
     }
 
     public static TsidBuilder forResource(BufferedByteStringAccessor byteStringAccessor, ResourceMetrics resourceMetrics) {
-        TsidBuilder tsidBuilder = new TsidBuilder(resourceMetrics.getResource().getAttributesCount() + 1);
+        TsidBuilder tsidBuilder = new TsidBuilder(resourceMetrics.getResource().getAttributesCount());
         new ResourceTsidFunnel(byteStringAccessor).add(resourceMetrics, tsidBuilder);
         return tsidBuilder;
     }
@@ -34,6 +34,5 @@ public static TsidBuilder forResource(BufferedByteStringAccessor byteStringAcces
     public void add(ResourceMetrics resourceMetrics, TsidBuilder tsidBuilder) {
         List<KeyValue> resourceAttributes = resourceMetrics.getResource().getAttributesList();
         tsidBuilder.add(resourceAttributes, AttributeListTsidFunnel.get(byteStringAccessor, "resource.attributes."));
-        byteStringAccessor.addStringDimension(tsidBuilder, "schema_url", resourceMetrics.getSchemaUrlBytes());
     }
 }

x-pack/plugin/otel-data/src/test/java/org/elasticsearch/xpack/oteldata/otlp/OtlpUtils.java

@@ -190,15 +190,13 @@ public static SummaryDataPoint createSummaryDataPoint(long timestamp, List<KeyVa
     }
 
     public static ExportMetricsServiceRequest createMetricsRequest(List<Metric> metrics) {
+        return createMetricsRequest(List.of(keyValue("service.name", "test-service")), metrics);
+    }
 
+    public static ExportMetricsServiceRequest createMetricsRequest(List<KeyValue> resourceAttributes, List<Metric> metrics) {
         List<ResourceMetrics> resourceMetrics = new ArrayList<>();
         for (Metric metric : metrics) {
-            resourceMetrics.add(
-                createResourceMetrics(
-                    List.of(keyValue("service.name", "test-service")),
-                    List.of(createScopeMetrics("test", "1.0.0", List.of(metric)))
-                )
-            );
+            resourceMetrics.add(createResourceMetrics(resourceAttributes, List.of(createScopeMetrics("test", "1.0.0", List.of(metric)))));
         }
 
         return ExportMetricsServiceRequest.newBuilder().addAllResourceMetrics(resourceMetrics).build();