Make distributor queryable select on series hint

Signed-off-by: Goutham Veeramachaneni <[email protected]>

Author: gouthamve

pkg/querier/distributor_queryable.go

@@ -84,7 +84,9 @@ func (q *distributorQuerier) Select(_ bool, sp *storage.SelectHints, matchers ..
 	// time range manipulation, otherwise we'll end up returning no series at all for
 	// older time ranges (while in Cortex we do ignore the start/end and always return
 	// series in ingesters).
-	if sp == nil {
+	// Also, in the recent versions of Prometheus, we pass in the hint but with Func set to "series".
+	// See: https://github.com/prometheus/prometheus/pull/8050
+	if sp == nil || sp.Func == "series" {
 		ms, err := q.distributor.MetricsForLabelMatchers(ctx, model.Time(q.mint), model.Time(q.maxt), matchers...)
 		if err != nil {
 			return storage.ErrSeriesSet(err)

pkg/querier/querier.go

@@ -275,7 +275,7 @@ func (q querier) Select(_ bool, sp *storage.SelectHints, matchers ...*labels.Mat
 	// Also, in the recent versions of Prometheus, we pass in the hint but with Func set to "series".
 	// See: https://github.com/prometheus/prometheus/pull/8050
 	if sp == nil || sp.Func == "series" {
-		return q.metadataQuerier.Select(true, nil, matchers...)
+		return q.metadataQuerier.Select(true, sp, matchers...)
 	}
 
 	userID, err := user.ExtractOrgID(ctx)