[ES|QL] Run aggregations on aggregate metric double with default metric

docs/changelog/138647.yaml

@@ -0,0 +1,6 @@
+pr: 138647
+summary: Run aggregations on aggregate metric double with default metric
+area: ES|QL
+type: feature
+issues:
+ - 136297

server/src/main/java/org/elasticsearch/index/mapper/NumberFieldMapper.java

@@ -2120,6 +2120,7 @@ public BlockLoader blockLoader(BlockLoaderContext blContext) {
                 return switch (cfg.function()) {
                     case MV_MAX -> type.blockLoaderFromDocValuesMvMax(name());
                     case MV_MIN -> type.blockLoaderFromDocValuesMvMin(name());
+                    case AMD_COUNT, AMD_DEFAULT, AMD_MAX, AMD_MIN, AMD_SUM -> type.blockLoaderFromDocValues(name());
                     default -> throw new UnsupportedOperationException("unknown fusion config [" + cfg.function() + "]");
                 };
             }
@@ -2140,7 +2141,7 @@ public BlockLoader blockLoader(BlockLoaderContext blContext) {
         public boolean supportsBlockLoaderConfig(BlockLoaderFunctionConfig config, FieldExtractPreference preference) {
             if (hasDocValues() && (preference != FieldExtractPreference.STORED || isSyntheticSource)) {
                 return switch (config.function()) {
-                    case MV_MAX, MV_MIN -> true;
+                    case AMD_MIN, AMD_MAX, AMD_SUM, AMD_COUNT, AMD_DEFAULT, MV_MAX, MV_MIN -> true;
                     default -> false;
                 };
             }

server/src/main/java/org/elasticsearch/index/mapper/blockloader/BlockLoaderFunctionConfig.java

@@ -46,6 +46,7 @@ public int hashCode() {
 
     enum Function {
         AMD_COUNT,
+        AMD_DEFAULT,
         AMD_MAX,
         AMD_MIN,
         AMD_SUM,

x-pack/plugin/esql/compute/src/main/java/org/elasticsearch/compute/data/AggregateMetricDoubleArrayBlock.java

@@ -353,6 +353,7 @@ public Block getMetricBlock(int index) {
     @Override
     public String toString() {
         String valuesString = Stream.of(AggregateMetricDoubleBlockBuilder.Metric.values())
+            .filter(metric -> metric != AggregateMetricDoubleBlockBuilder.Metric.DEFAULT)
             .map(metric -> metric.getLabel() + "=" + getMetricBlock(metric.getIndex()))
             .collect(Collectors.joining(", ", "[", "]"));
 

x-pack/plugin/esql/compute/src/main/java/org/elasticsearch/compute/data/AggregateMetricDoubleBlockBuilder.java

@@ -186,7 +186,8 @@ public enum Metric {
         MIN(0, "min"),
         MAX(1, "max"),
         SUM(2, "sum"),
-        COUNT(3, "value_count");
+        COUNT(3, "value_count"),
+        DEFAULT(4, "default");
 
         private final int index;
         private final String label;
@@ -210,6 +211,7 @@ public static Metric indexToMetric(int i) {
                 case 1 -> MAX;
                 case 2 -> SUM;
                 case 3 -> COUNT;
+                case 4 -> DEFAULT;
                 default -> null;
             };
         }

x-pack/plugin/esql/qa/testFixtures/src/main/resources/k8s-timeseries.csv-spec

@@ -1138,3 +1138,59 @@ max_deriv:double | max_rate:double | time_bucket:date_nanos   | cluster:keyword
 16.0871          | 11.8608         | 2024-05-10T00:15:00.000Z | prod
 10.2206          | 6.9807          | 2024-05-10T00:20:00.000Z | prod
 ;
+
+DefaultMetricWithFrom
+required_capability: ts_command_v0
+required_capability: aggregate_metric_double_default_metric
+FROM k8s-downsampled
+| STATS max = max(network.eth0.tx), std_dev = ROUND(STD_DEV(network.eth0.tx), 7) by pod
+| sort pod
+;
+
+max:double | std_dev:double | pod:keyword
+1060.0     | 331.5018947    | one
+824.0      | 151.9744943    | three
+1419.0     | 364.4118888    | two
+;
+
+DefaultMetricWithTS
+required_capability: ts_command_v0
+required_capability: aggregate_metric_double_default_metric
+TS k8s-downsampled
+| STATS max = max(network.eth0.tx), std_dev = ROUND(STD_DEV(network.eth0.tx), 7) by pod
+| sort pod
+;
+
+max:double | std_dev:double | pod:keyword
+1060.0     | 355.3786713    | one
+824.0      | 180.6918802    | three
+815.0      | 102.3469046    | two
+;
+
+DefaultMetricWithFromImplicitCasting
+required_capability: ts_command_v0
+required_capability: aggregate_metric_double_default_metric
+FROM k8s*
+| STATS min = min(network.eth0.tx), std_dev = ROUND(STD_DEV(network.eth0.tx), 7) by pod
+| sort pod
+;
+
+min:double | std_dev:double | pod:keyword
+18.0       | 380.8643432    | one
+48.0       | 340.5483293    | three
+20.0       | 431.2070165    | two
+;
+
+DefaultMetricWithTSImplicitCasting
+required_capability: ts_command_v0
+required_capability: aggregate_metric_double_default_metric
+TS k8s*
+| STATS min = min(network.eth0.tx), std_dev = ROUND(STD_DEV(network.eth0.tx), 7) by pod
+| sort pod
+;
+
+min:double | std_dev:double | pod:keyword
+193.0      | 427.9853269    | one
+715.0      | 208.6955678    | three
+602.0      | 375.7757842    | two
+;

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/action/EsqlCapabilities.java

@@ -959,6 +959,11 @@ public enum Cap {
          */
         AGGREGATE_METRIC_DOUBLE_V0,
 
+        /**
+         * Support running all aggregations on aggregate_metric_double using the default metric
+         */
+        AGGREGATE_METRIC_DOUBLE_DEFAULT_METRIC,
+
         /**
          * Support change point detection "CHANGE_POINT".
          */