Move capabilities and add comment about substitute surrogates

Author: limotova

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

@@ -890,6 +890,31 @@ public enum Cap {
          */
         AGGREGATE_METRIC_DOUBLE_PARTIAL_SUBMETRICS(AGGREGATE_METRIC_DOUBLE_FEATURE_FLAG),
 
+        /**
+         * Support for rendering aggregate_metric_double type
+         */
+        AGGREGATE_METRIC_DOUBLE_RENDERING(AGGREGATE_METRIC_DOUBLE_FEATURE_FLAG),
+
+        /**
+         * Support for to_aggregate_metric_double function
+         */
+        AGGREGATE_METRIC_DOUBLE_CONVERT_TO(AGGREGATE_METRIC_DOUBLE_FEATURE_FLAG),
+
+        /**
+         * Support for sorting when aggregate_metric_doubles are present
+         */
+        AGGREGATE_METRIC_DOUBLE_SORTING(AGGREGATE_METRIC_DOUBLE_FEATURE_FLAG),
+
+        /**
+         * Support avg with aggregate metric doubles
+         */
+        AGGREGATE_METRIC_DOUBLE_AVG(AGGREGATE_METRIC_DOUBLE_FEATURE_FLAG),
+
+        /**
+         * Support for implicit casting of aggregate metric double when run in aggregations
+         */
+        AGGREGATE_METRIC_DOUBLE_IMPLICIT_CASTING_IN_AGGS(AGGREGATE_METRIC_DOUBLE_FEATURE_FLAG),
+
         /**
          * Support change point detection "CHANGE_POINT".
          */
@@ -913,11 +938,6 @@ public enum Cap {
          */
         SUPPORT_PARTIAL_RESULTS,
 
-        /**
-         * Support for rendering aggregate_metric_double type
-         */
-        AGGREGATE_METRIC_DOUBLE_RENDERING(AGGREGATE_METRIC_DOUBLE_FEATURE_FLAG),
-
         /**
          * Support for RERANK command
          */
@@ -969,11 +989,6 @@ public enum Cap {
          */
         NON_FULL_TEXT_FUNCTIONS_SCORING,
 
-        /**
-         * Support for to_aggregate_metric_double function
-         */
-        AGGREGATE_METRIC_DOUBLE_CONVERT_TO(AGGREGATE_METRIC_DOUBLE_FEATURE_FLAG),
-
         /**
          * The {@code _query} API now reports the original types.
          */
@@ -1000,11 +1015,6 @@ public enum Cap {
          */
         MAKE_NUMBER_OF_CHANNELS_CONSISTENT_WITH_LAYOUT,
 
-        /**
-         * Support for sorting when aggregate_metric_doubles are present
-         */
-        AGGREGATE_METRIC_DOUBLE_SORTING(AGGREGATE_METRIC_DOUBLE_FEATURE_FLAG),
-
         /**
          * Supercedes {@link Cap#MAKE_NUMBER_OF_CHANNELS_CONSISTENT_WITH_LAYOUT}.
          */
@@ -1228,17 +1238,7 @@ public enum Cap {
         /**
          * FUSE command
          */
-        FUSE(Build.current().isSnapshot()),
-
-        /**
-         * Support avg with aggregate metric doubles
-         */
-        AGGREGATE_METRIC_DOUBLE_AVG(AGGREGATE_METRIC_DOUBLE_FEATURE_FLAG),
-
-        /**
-         * Support for implicit casting of aggregate metric double when run in aggregations
-         */
-        AGGREGATE_METRIC_DOUBLE_IMPLICIT_CASTING_IN_AGGS(AGGREGATE_METRIC_DOUBLE_FEATURE_FLAG);
+        FUSE(Build.current().isSnapshot());
 
         private final boolean enabled;
 

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/analysis/Analyzer.java

@@ -1998,6 +1998,10 @@ private LogicalPlan doRule(Aggregate plan) {
                         return aggFunc;
                     }
                     if (aggFunc instanceof Avg || aggFunc instanceof AvgOverTime) {
+                        // This is related to a known bug involving AvgOverTime and aggregate_metric_double. We substitute
+                        // surrogates here so when AvgOverTime becomes Div(SumOverTime, CountOverTime), which then becomes
+                        // Div(SumOverTime(agg_metric.sum), SumOverTime(agg_metric.count)), we can distinguish between the
+                        // SumOverTimes produced here from references to Sum/CountOverTime in other parts of the query
                         return ((SurrogateExpression) aggFunc).surrogate();
                     }
                     Map<String, Expression> typeConverters = typeConverters(aggFunc, fa, mtf);