[Star Tree] Add date dimension support for range aggregation validation

This change extends the star-tree range aggregation validation to support
DateDimension in addition to NumericDimension. Previously, range aggregations
with star-tree optimization only worked with numeric fields. Now date fields
can also leverage star-tree indexes for range aggregations.

Signed-off-by: Anand Kumar Shaw <anandkrshawheritage@gmail.com>

Author: Anand Kumar Shaw

CHANGELOG.md

@@ -15,6 +15,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Add a dynamic setting to change skip_cache_factor and min_frequency for querycache ([#18351](https://github.com/opensearch-project/OpenSearch/issues/18351))
 - Add overload constructor for Translog to accept Channel Factory as a parameter ([#18918](https://github.com/opensearch-project/OpenSearch/pull/18918))
 - Add subdirectory-aware store module with recovery support ([#19132](https://github.com/opensearch-project/OpenSearch/pull/19132))
+- [Star Tree] Add support for date type dimensions in range aggregation validation ([#20460](https://github.com/opensearch-project/OpenSearch/pull/20460))
 
 ### Changed
 - Add CompletionStage variants to methods in the Client Interface and default to ActionListener impl ([#18998](https://github.com/opensearch-project/OpenSearch/pull/18998))

server/src/main/java/org/opensearch/search/startree/StarTreeQueryContext.java

@@ -176,12 +176,12 @@ private static boolean validateRangeAggregationSupport(
             return false;
         }
 
-        // Validate request field is part of dimensions & is a numeric field
-        // TODO: Add support for date type ranges
+        // Validate request field is part of dimensions & is a numeric or date field
         if (compositeIndexFieldInfo.getDimensions()
             .stream()
             .noneMatch(
-                dimension -> rangeAggregatorFactory.getField().equals(dimension.getField()) && dimension instanceof NumericDimension
+                dimension -> rangeAggregatorFactory.getField().equals(dimension.getField())
+                    && (dimension instanceof NumericDimension || dimension instanceof DateDimension)
             )) {
             return false;
         }

server/src/test/java/org/opensearch/search/SearchServiceStarTreeTests.java

@@ -910,11 +910,33 @@ public void testQueryParsingForRangeAggregations() throws IOException {
         sourceBuilder = new SearchSourceBuilder().size(0).query(baseQuery).aggregation(rangeAggregationBuilder);
         assertStarTreeContext(request, sourceBuilder, null, -1);
 
-        // Case 6: Range Aggregation on non-numeric field, should not use star tree
+        // Case 6: Range Aggregation on date field with DateDimension in star-tree, should use star tree
         rangeAggregationBuilder = range("range").field(TIMESTAMP_FIELD).addRange(0, 100).subAggregation(maxAggNoSub);
         baseQuery = new MatchAllQueryBuilder();
         sourceBuilder = new SearchSourceBuilder().size(0).query(baseQuery).aggregation(rangeAggregationBuilder);
-        assertStarTreeContext(request, sourceBuilder, null, -1);
+        assertStarTreeContext(
+            request,
+            sourceBuilder,
+            getStarTreeQueryContext(
+                searchContext,
+                starTreeFieldConfiguration,
+                "startree1",
+                -1,
+                List.of(
+                    new DateDimension(
+                        TIMESTAMP_FIELD,
+                        List.of(new DateTimeUnitAdapter(Rounding.DateTimeUnit.MONTH_OF_YEAR)),
+                        DateFieldMapper.Resolution.MILLISECONDS
+                    ),
+                    new OrdinalDimension(KEYWORD_FIELD)
+                ),
+                List.of(new Metric(STATUS, List.of(MetricStat.SUM, MetricStat.MAX))),
+                baseQuery,
+                sourceBuilder,
+                true
+            ),
+            -1
+        );
 
         // Case 7: Valid range aggregation and valid metric aggregation, should use star tree & cache
         rangeAggregationBuilder = range("range").field(NUMERIC_FIELD).addRange(0, 100).subAggregation(maxAggNoSub);