rebased

Signed-off-by: Krasi Georgiev <8903888+krasi-georgiev@users.noreply.github.com>

CHANGELOG.md

@@ -22,7 +22,6 @@ We use *breaking* word for marking changes that are not backward compatible (rel
 - [#2895](https://github.com/thanos-io/thanos/pull/2895) Compact: Fix increment of `thanos_compact_downsample_total` metric for downsample of 5m resolution blocks.
 - [#2858](https://github.com/thanos-io/thanos/pull/2858) Store: Fix `--store.grpc.series-sample-limit` implementation. The limit is now applied to the sum of all samples fetched across all queried blocks via a single Series call, instead of applying it individually to each block.
 - [#2936](https://github.com/thanos-io/thanos/pull/2936) Compact: Fix ReplicaLabelRemover panic when replicaLabels are not specified.
-- [#3010](https://github.com/thanos-io/thanos/pull/3010) Querier: Data gaps when switching iterators.
 - [#2956](https://github.com/thanos-io/thanos/pull/2956) Store: Fix fetching of chunks bigger than 16000 bytes.
 - [#2970](https://github.com/thanos-io/thanos/pull/2970) Store: Upgrade minio-go/v7 to fix slowness when running on EKS.
 - [#2976](https://github.com/thanos-io/thanos/pull/2976) Query: Better rounding for incoming query timestamps.

pkg/api/query/v1.go

@@ -486,6 +486,15 @@ func (qapi *QueryAPI) series(r *http.Request) (interface{}, []error, *api.ApiErr
 		return nil, nil, &api.ApiError{Typ: api.ErrorBadData, Err: err}
 	}
 
+	var step time.Duration
+	if t := r.FormValue("step"); t != "" {
+		var err error
+		step, err = parseDuration(t)
+		if err != nil {
+			return nil, nil, &api.ApiError{Typ: api.ErrorBadData, Err: err}
+		}
+	}
+
 	var matcherSets [][]*labels.Matcher
 	for _, s := range r.Form["match[]"] {
 		matchers, err := parser.ParseMetricSelector(s)
@@ -526,8 +535,14 @@ func (qapi *QueryAPI) series(r *http.Request) (interface{}, []error, *api.ApiErr
 		metrics = []labels.Labels{}
 		sets    []storage.SeriesSet
 	)
+
+	hints := &storage.SelectHints{
+		Start: timestamp.FromTime(start),
+		End:   timestamp.FromTime(end),
+		Step:  int64(step),
+	}
 	for _, mset := range matcherSets {
-		sets = append(sets, q.Select(false, nil, mset...))
+		sets = append(sets, q.Select(false, hints, mset...))
 	}
 
 	set := storage.NewMergeSeriesSet(sets, storage.ChainedSeriesMerge)