Optimize ordinal inputs in Values aggregation

benchmarks/src/main/java/org/elasticsearch/benchmark/compute/operator/ValuesAggregatorBenchmark.java

@@ -21,10 +21,13 @@
 import org.elasticsearch.compute.data.Block;
 import org.elasticsearch.compute.data.BlockFactory;
 import org.elasticsearch.compute.data.BytesRefBlock;
+import org.elasticsearch.compute.data.BytesRefVector;
 import org.elasticsearch.compute.data.ElementType;
 import org.elasticsearch.compute.data.IntBlock;
+import org.elasticsearch.compute.data.IntVector;
 import org.elasticsearch.compute.data.LongBlock;
 import org.elasticsearch.compute.data.LongVector;
+import org.elasticsearch.compute.data.OrdinalBytesRefVector;
 import org.elasticsearch.compute.data.Page;
 import org.elasticsearch.compute.operator.AggregationOperator;
 import org.elasticsearch.compute.operator.DriverContext;
@@ -282,11 +285,18 @@ private static Block dataBlock(int groups, String dataType) {
         int blockLength = blockLength(groups);
         return switch (dataType) {
             case BYTES_REF -> {
-                try (BytesRefBlock.Builder builder = blockFactory.newBytesRefBlockBuilder(blockLength)) {
+                try (
+                    BytesRefVector.Builder dict = blockFactory.newBytesRefVectorBuilder(blockLength);
+                    IntVector.Builder ords = blockFactory.newIntVectorBuilder(blockLength)
+                ) {
+                    final int dictLength = Math.min(blockLength, KEYWORDS.length);
+                    for (int i = 0; i < dictLength; i++) {
+                        dict.appendBytesRef(KEYWORDS[i]);
+                    }
                     for (int i = 0; i < blockLength; i++) {
-                        builder.appendBytesRef(KEYWORDS[i % KEYWORDS.length]);
+                        ords.appendInt(i % dictLength);
                     }
-                    yield builder.build();
+                    yield new OrdinalBytesRefVector(ords.build(), dict.build()).asBlock();
                 }
             }
             case INT -> {

docs/changelog/127849.yaml

@@ -0,0 +1,5 @@
+pr: 127849
+summary: Optimize ordinal inputs in Values aggregation
+area: "ES|QL, TSDB"
+type: enhancement
+issues: []

x-pack/plugin/esql/compute/gen/src/main/java/org/elasticsearch/compute/gen/GroupingAggregatorImplementer.java

@@ -35,6 +35,7 @@
 
 import static java.util.stream.Collectors.joining;
 import static org.elasticsearch.compute.gen.AggregatorImplementer.capitalize;
+import static org.elasticsearch.compute.gen.Methods.optionalStaticMethod;
 import static org.elasticsearch.compute.gen.Methods.requireAnyArgs;
 import static org.elasticsearch.compute.gen.Methods.requireAnyType;
 import static org.elasticsearch.compute.gen.Methods.requireArgs;
@@ -336,10 +337,32 @@ private MethodSpec prepareProcessPage() {
             builder.beginControlFlow("if (valuesBlock.mayHaveNulls())");
             builder.addStatement("state.enableGroupIdTracking(seenGroupIds)");
             builder.endControlFlow();
-            builder.addStatement("return $L", addInput(b -> b.addStatement("addRawInput(positionOffset, groupIds, valuesBlock$L)", extra)));
+            if (shouldWrapAddInput(blockType(aggParam.type()))) {
+                builder.addStatement(
+                    "var addInput = $L",
+                    addInput(b -> b.addStatement("addRawInput(positionOffset, groupIds, valuesBlock$L)", extra))
+                );
+                builder.addStatement("return $T.wrapAddInput(addInput, state, valuesBlock)", declarationType);
+            } else {
+                builder.addStatement(
+                    "return $L",
+                    addInput(b -> b.addStatement("addRawInput(positionOffset, groupIds, valuesBlock$L)", extra))
+                );
+            }
         }
         builder.endControlFlow();
-        builder.addStatement("return $L", addInput(b -> b.addStatement("addRawInput(positionOffset, groupIds, valuesVector$L)", extra)));
+        if (shouldWrapAddInput(vectorType(aggParam.type()))) {
+            builder.addStatement(
+                "var addInput = $L",
+                addInput(b -> b.addStatement("addRawInput(positionOffset, groupIds, valuesVector$L)", extra))
+            );
+            builder.addStatement("return $T.wrapAddInput(addInput, state, valuesVector)", declarationType);
+        } else {
+            builder.addStatement(
+                "return $L",
+                addInput(b -> b.addStatement("addRawInput(positionOffset, groupIds, valuesVector$L)", extra))
+            );
+        }
         return builder.build();
     }
 
@@ -526,6 +549,15 @@ private void combineRawInputForArray(MethodSpec.Builder builder, String arrayVar
         warningsBlock(builder, () -> builder.addStatement("$T.combine(state, groupId, $L)", declarationType, arrayVariable));
     }
 
+    private boolean shouldWrapAddInput(TypeName valuesType) {
+        return optionalStaticMethod(
+            declarationType,
+            requireType(GROUPING_AGGREGATOR_FUNCTION_ADD_INPUT),
+            requireName("wrapAddInput"),
+            requireArgs(requireType(GROUPING_AGGREGATOR_FUNCTION_ADD_INPUT), requireType(aggState.declaredType()), requireType(valuesType))
+        ) != null;
+    }
+
     private void warningsBlock(MethodSpec.Builder builder, Runnable block) {
         if (warnExceptions.isEmpty() == false) {
             builder.beginControlFlow("try");

x-pack/plugin/esql/compute/gen/src/main/java/org/elasticsearch/compute/gen/Methods.java

@@ -59,20 +59,31 @@ static ExecutableElement requireStaticMethod(
         TypeMatcher returnTypeMatcher,
         NameMatcher nameMatcher,
         ArgumentMatcher argumentMatcher
+    ) {
+        ExecutableElement method = optionalStaticMethod(declarationType, returnTypeMatcher, nameMatcher, argumentMatcher);
+        if (method == null) {
+            var message = nameMatcher.names.size() == 1 ? "Requires method: " : "Requires one of methods: ";
+            var signatures = nameMatcher.names.stream()
+                .map(name -> "public static " + returnTypeMatcher + " " + declarationType + "#" + name + "(" + argumentMatcher + ")")
+                .collect(joining(" or "));
+            throw new IllegalArgumentException(message + signatures);
+        }
+        return method;
+    }
+
+    static ExecutableElement optionalStaticMethod(
+        TypeElement declarationType,
+        TypeMatcher returnTypeMatcher,
+        NameMatcher nameMatcher,
+        ArgumentMatcher argumentMatcher
     ) {
         return typeAndSuperType(declarationType).flatMap(type -> ElementFilter.methodsIn(type.getEnclosedElements()).stream())
             .filter(method -> method.getModifiers().contains(Modifier.STATIC))
             .filter(method -> nameMatcher.test(method.getSimpleName().toString()))
             .filter(method -> returnTypeMatcher.test(TypeName.get(method.getReturnType())))
             .filter(method -> argumentMatcher.test(method.getParameters().stream().map(it -> TypeName.get(it.asType())).toList()))
             .findFirst()
-            .orElseThrow(() -> {
-                var message = nameMatcher.names.size() == 1 ? "Requires method: " : "Requires one of methods: ";
-                var signatures = nameMatcher.names.stream()
-                    .map(name -> "public static " + returnTypeMatcher + " " + declarationType + "#" + name + "(" + argumentMatcher + ")")
-                    .collect(joining(" or "));
-                return new IllegalArgumentException(message + signatures);
-            });
+            .orElse(null);
     }
 
     static NameMatcher requireName(String... names) {