Prometheus: Fix interpolating minStep for range queries when incremental querying enabled (#107715)

* return calculatedMinStep in first frame of the response

* update test files

* make the custom metadata as type of map[string]any

* append calculatedMinStep to custom metadata

* fix exemplar frame checking

pkg/promlib/converter/prom.go

@@ -1140,8 +1140,8 @@ streamField:
 	return parsedLabelsMap, structuredMetadataMap, nil
 }
 
-func resultTypeToCustomMeta(resultType string) map[string]string {
-	return map[string]string{"resultType": resultType}
+func resultTypeToCustomMeta(resultType string) map[string]any {
+	return map[string]any{"resultType": resultType}
 }
 
 func timeFromFloat(fv float64) time.Time {

pkg/promlib/models/result.go

@@ -20,7 +20,7 @@ func ResultTypeFromFrame(frame *data.Frame) ResultType {
 	if frame.Meta.Custom == nil {
 		return ResultTypeUnknown
 	}
-	custom, ok := frame.Meta.Custom.(map[string]string)
+	custom, ok := frame.Meta.Custom.(map[string]any)
 	if !ok {
 		return ResultTypeUnknown
 	}

pkg/promlib/querydata/response.go

@@ -54,6 +54,14 @@ func (s *QueryData) parseResponse(ctx context.Context, q *models.Query, res *htt
 			addMetadataToMultiFrame(q, frame)
 			if i == 0 {
 				frame.Meta.ExecutedQueryString = executedQueryString(q)
+				if frame.Meta.Custom == nil {
+					frame.Meta.Custom = make(map[string]any)
+				}
+				if custom, ok := frame.Meta.Custom.(map[string]any); ok {
+					// This is required for incremental querying feature
+					// Knowing the calculated minStep is required for merging and caching the frames on frontend side
+					custom["calculatedMinStep"] = q.Step.Milliseconds()
+				}
 			}
 		}
 

pkg/promlib/testdata/range_auto.result.golden.jsonc

@@ -7,6 +7,7 @@
 //          1
 //      ],
 //      "custom": {
+//          "calculatedMinStep": 1000,
 //          "resultType": "matrix"
 //      },
 //      "executedQueryString": "Expr: histogram_quantile(0.95, sum(rate(tns_request_duration_seconds_bucket[4s])) by (le))\nStep: 1s"
@@ -44,6 +45,7 @@
             1
           ],
           "custom": {
+            "calculatedMinStep": 1000,
             "resultType": "matrix"
           },
           "executedQueryString": "Expr: histogram_quantile(0.95, sum(rate(tns_request_duration_seconds_bucket[4s])) by (le))\nStep: 1s"

pkg/promlib/testdata/range_infinity.result.golden.jsonc

@@ -7,6 +7,7 @@
 //          1
 //      ],
 //      "custom": {
+//          "calculatedMinStep": 1000,
 //          "resultType": "matrix"
 //      },
 //      "executedQueryString": "Expr: 1 / 0\nStep: 1s"
@@ -37,6 +38,7 @@
             1
           ],
           "custom": {
+            "calculatedMinStep": 1000,
             "resultType": "matrix"
           },
           "executedQueryString": "Expr: 1 / 0\nStep: 1s"

pkg/promlib/testdata/range_missing.result.golden.jsonc

@@ -7,6 +7,7 @@
 //          1
 //      ],
 //      "custom": {
+//          "calculatedMinStep": 1000,
 //          "resultType": "matrix"
 //      },
 //      "executedQueryString": "Expr: test1\nStep: 1s"
@@ -37,6 +38,7 @@
             1
           ],
           "custom": {
+            "calculatedMinStep": 1000,
             "resultType": "matrix"
           },
           "executedQueryString": "Expr: test1\nStep: 1s"

pkg/promlib/testdata/range_nan.result.golden.jsonc

@@ -7,6 +7,7 @@
 //          1
 //      ],
 //      "custom": {
+//          "calculatedMinStep": 1000,
 //          "resultType": "matrix"
 //      },
 //      "executedQueryString": "Expr: \nStep: 1s"
@@ -37,6 +38,7 @@
             1
           ],
           "custom": {
+            "calculatedMinStep": 1000,
             "resultType": "matrix"
           },
           "executedQueryString": "Expr: \nStep: 1s"

pkg/promlib/testdata/range_simple.result.golden.jsonc

@@ -7,6 +7,7 @@
 //          1
 //      ],
 //      "custom": {
+//          "calculatedMinStep": 1000,
 //          "resultType": "matrix"
 //      },
 //      "executedQueryString": "Expr: \nStep: 1s"
@@ -60,6 +61,7 @@
             1
           ],
           "custom": {
+            "calculatedMinStep": 1000,
             "resultType": "matrix"
           },
           "executedQueryString": "Expr: \nStep: 1s"