Elasticsearch: Fix adding correct min_doc_count to all aggregation types in backend implementation (#59713)

* Elasticsearch: Fix adding correct min_doc_count to all aggregation types in backend implementation

* Update snapshot tests

* Fix linting

pkg/tsdb/elasticsearch/testdata_request/metric_complex.request.line1.json

@@ -29,6 +29,7 @@
       },
       "terms": {
         "field": "label",
+        "min_doc_count": 1,
         "order": {
           "_key": "desc"
         },

pkg/tsdb/elasticsearch/testdata_request/metric_simple.request.line1.json

@@ -17,6 +17,7 @@
             },
             "terms": {
                 "field": "label",
+                "min_doc_count": 1,
                 "order": {
                     "_key": "desc"
                 },

pkg/tsdb/elasticsearch/time_series_query.go

@@ -227,11 +227,7 @@ func (metricAggregation MetricAgg) generateSettingsForDSL() map[string]interface
 }
 
 func (bucketAgg BucketAgg) generateSettingsForDSL() map[string]interface{} {
-	// TODO: This might also need to be applied to other bucket aggregations and other fields.
-	switch bucketAgg.Type {
-	case "date_histogram":
-		setIntPath(bucketAgg.Settings, "min_doc_count")
-	}
+	setIntPath(bucketAgg.Settings, "min_doc_count")
 
 	return bucketAgg.Settings.MustMap()
 }

pkg/tsdb/elasticsearch/time_series_query_test.go

@@ -310,9 +310,9 @@ func TestExecuteTimeSeriesQuery(t *testing.T) {
 			sr := c.multisearchRequests[0].Requests[0]
 			firstLevel := sr.Aggs[0]
 			require.Equal(t, firstLevel.Key, "2")
-			// FIXME: This is a bug in the current implementation. The min_doc_count is not set.
-			// termsAgg := firstLevel.Aggregation.Aggregation.(*es.TermsAggregation)
-			// require.Equal(t, termsAgg.MinDocCount, "1")
+			termsAgg := firstLevel.Aggregation.Aggregation.(*es.TermsAggregation)
+			expectedMinDocCount := 1
+			require.Equal(t, termsAgg.MinDocCount, &expectedMinDocCount)
 		})
 
 		t.Run("With metric percentiles", func(t *testing.T) {