diff --git a/app/vmselect/netstorage/netstorage.go b/app/vmselect/netstorage/netstorage.go
index e237289780..01755db7c4 100644
--- a/app/vmselect/netstorage/netstorage.go
+++ b/app/vmselect/netstorage/netstorage.go
@@ -523,20 +523,20 @@ func mergeSortBlocks(dst *Result, sbh sortBlocksHeap, dedupInterval int64) {
 		}
 		sbNext := sbh[0]
 		tsNext := sbNext.Timestamps[sbNext.NextIdx]
-		idxNext := len(top.Timestamps)
-		if top.Timestamps[idxNext-1] > tsNext {
-			idxNext = top.NextIdx
-			for top.Timestamps[idxNext] <= tsNext {
-				idxNext++
-			}
+		topTimestamps := top.Timestamps
+		topNextIdx := top.NextIdx
+		if n := equalTimestampsPrefix(topTimestamps[topNextIdx:], sbNext.Timestamps[sbNext.NextIdx:]); n > 0 && dedupInterval > 0 {
+			// Skip n replicated samples at top if deduplication is enabled.
+			top.NextIdx = topNextIdx + n
+		} else {
+			// Copy samples from top to dst with timestamps not exceeding tsNext.
+			top.NextIdx = topNextIdx + binarySearchTimestamps(topTimestamps[topNextIdx:], tsNext)
+			dst.Timestamps = append(dst.Timestamps, topTimestamps[topNextIdx:top.NextIdx]...)
+			dst.Values = append(dst.Values, top.Values[topNextIdx:top.NextIdx]...)
 		}
-		dst.Timestamps = append(dst.Timestamps, top.Timestamps[top.NextIdx:idxNext]...)
-		dst.Values = append(dst.Values, top.Values[top.NextIdx:idxNext]...)
-		if idxNext < len(top.Timestamps) {
-			top.NextIdx = idxNext
+		if top.NextIdx < len(topTimestamps) {
 			heap.Push(&sbh, top)
 		} else {
-			// Return top to the pool.
 			putSortBlock(top)
 		}
 	}
@@ -549,6 +549,34 @@ func mergeSortBlocks(dst *Result, sbh sortBlocksHeap, dedupInterval int64) {
 
 var dedupsDuringSelect = metrics.NewCounter(`vm_deduplicated_samples_total{type="select"}`)
 
+func equalTimestampsPrefix(a, b []int64) int {
+	for i, v := range a {
+		if i >= len(b) || v != b[i] {
+			return i
+		}
+	}
+	return len(a)
+}
+
+func binarySearchTimestamps(timestamps []int64, ts int64) int {
+	// The code has been adapted from sort.Search.
+	n := len(timestamps)
+	if n > 0 && timestamps[n-1] < ts {
+		// Fast path for values scanned in ascending order.
+		return n
+	}
+	i, j := 0, n
+	for i < j {
+		h := int(uint(i+j) >> 1)
+		if h >= 0 && h < len(timestamps) && timestamps[h] <= ts {
+			i = h + 1
+		} else {
+			j = h
+		}
+	}
+	return i
+}
+
 type sortBlock struct {
 	Timestamps []int64
 	Values     []float64
diff --git a/app/vmselect/netstorage/netstorage_test.go b/app/vmselect/netstorage/netstorage_test.go
new file mode 100644
index 0000000000..6de0d268d7
--- /dev/null
+++ b/app/vmselect/netstorage/netstorage_test.go
@@ -0,0 +1,179 @@
+package netstorage
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestMergeSortBlocks(t *testing.T) {
+	f := func(blocks []*sortBlock, dedupInterval int64, expectedResult *Result) {
+		t.Helper()
+		var result Result
+		mergeSortBlocks(&result, blocks, dedupInterval)
+		if !reflect.DeepEqual(result.Values, expectedResult.Values) {
+			t.Fatalf("unexpected values;\ngot\n%v\nwant\n%v", result.Values, expectedResult.Values)
+		}
+		if !reflect.DeepEqual(result.Timestamps, expectedResult.Timestamps) {
+			t.Fatalf("unexpected timestamps;\ngot\n%v\nwant\n%v", result.Timestamps, expectedResult.Timestamps)
+		}
+	}
+
+	// Zero blocks
+	f(nil, 1, &Result{})
+
+	// Single block without samples
+	f([]*sortBlock{{}}, 1, &Result{})
+
+	// Single block with a single samples.
+	f([]*sortBlock{
+		{
+			Timestamps: []int64{1},
+			Values:     []float64{4.2},
+		},
+	}, 1, &Result{
+		Timestamps: []int64{1},
+		Values:     []float64{4.2},
+	})
+
+	// Single block with multiple samples.
+	f([]*sortBlock{
+		{
+			Timestamps: []int64{1, 2, 3},
+			Values:     []float64{4.2, 2.1, 10},
+		},
+	}, 1, &Result{
+		Timestamps: []int64{1, 2, 3},
+		Values:     []float64{4.2, 2.1, 10},
+	})
+
+	// Single block with multiple samples with deduplication.
+	f([]*sortBlock{
+		{
+			Timestamps: []int64{1, 2, 3},
+			Values:     []float64{4.2, 2.1, 10},
+		},
+	}, 2, &Result{
+		Timestamps: []int64{2, 3},
+		Values:     []float64{2.1, 10},
+	})
+
+	// Multiple blocks without time range intersection.
+	f([]*sortBlock{
+		{
+			Timestamps: []int64{3, 5},
+			Values:     []float64{5.2, 6.1},
+		},
+		{
+			Timestamps: []int64{1, 2},
+			Values:     []float64{4.2, 2.1},
+		},
+	}, 1, &Result{
+		Timestamps: []int64{1, 2, 3, 5},
+		Values:     []float64{4.2, 2.1, 5.2, 6.1},
+	})
+
+	// Multiple blocks with time range intersection.
+	f([]*sortBlock{
+		{
+			Timestamps: []int64{3, 5},
+			Values:     []float64{5.2, 6.1},
+		},
+		{
+			Timestamps: []int64{1, 2, 4},
+			Values:     []float64{4.2, 2.1, 42},
+		},
+	}, 1, &Result{
+		Timestamps: []int64{1, 2, 3, 4, 5},
+		Values:     []float64{4.2, 2.1, 5.2, 42, 6.1},
+	})
+
+	// Multiple blocks with time range inclusion.
+	f([]*sortBlock{
+		{
+			Timestamps: []int64{0, 3, 5},
+			Values:     []float64{9, 5.2, 6.1},
+		},
+		{
+			Timestamps: []int64{1, 2, 4},
+			Values:     []float64{4.2, 2.1, 42},
+		},
+	}, 1, &Result{
+		Timestamps: []int64{0, 1, 2, 3, 4, 5},
+		Values:     []float64{9, 4.2, 2.1, 5.2, 42, 6.1},
+	})
+
+	// Multiple blocks with identical timestamps.
+	f([]*sortBlock{
+		{
+			Timestamps: []int64{1, 2, 4},
+			Values:     []float64{9, 5.2, 6.1},
+		},
+		{
+			Timestamps: []int64{1, 2, 4},
+			Values:     []float64{4.2, 2.1, 42},
+		},
+	}, 1, &Result{
+		Timestamps: []int64{1, 2, 4},
+		Values:     []float64{4.2, 2.1, 42},
+	})
+
+	// Multiple blocks with identical timestamps, disabled deduplication.
+	f([]*sortBlock{
+		{
+			Timestamps: []int64{1, 2, 4},
+			Values:     []float64{9, 5.2, 6.1},
+		},
+		{
+			Timestamps: []int64{1, 2, 4},
+			Values:     []float64{4.2, 2.1, 42},
+		},
+	}, 0, &Result{
+		Timestamps: []int64{1, 1, 2, 2, 4, 4},
+		Values:     []float64{9, 4.2, 2.1, 5.2, 6.1, 42},
+	})
+
+	// Multiple blocks with identical timestamp ranges.
+	f([]*sortBlock{
+		{
+			Timestamps: []int64{1, 2, 5, 10, 11},
+			Values:     []float64{9, 8, 7, 6, 5},
+		},
+		{
+			Timestamps: []int64{1, 2, 4, 10, 11, 12},
+			Values:     []float64{21, 22, 23, 24, 25, 26},
+		},
+	}, 1, &Result{
+		Timestamps: []int64{1, 2, 4, 5, 10, 11, 12},
+		Values:     []float64{21, 22, 23, 7, 24, 5, 26},
+	})
+
+	// Multiple blocks with identical timestamp ranges, no deduplication.
+	f([]*sortBlock{
+		{
+			Timestamps: []int64{1, 2, 5, 10, 11},
+			Values:     []float64{9, 8, 7, 6, 5},
+		},
+		{
+			Timestamps: []int64{1, 2, 4, 10, 11, 12},
+			Values:     []float64{21, 22, 23, 24, 25, 26},
+		},
+	}, 0, &Result{
+		Timestamps: []int64{1, 1, 2, 2, 4, 5, 10, 10, 11, 11, 12},
+		Values:     []float64{9, 21, 22, 8, 23, 7, 6, 24, 25, 5, 26},
+	})
+
+	// Multiple blocks with identical timestamp ranges with deduplication.
+	f([]*sortBlock{
+		{
+			Timestamps: []int64{1, 2, 5, 10, 11},
+			Values:     []float64{9, 8, 7, 6, 5},
+		},
+		{
+			Timestamps: []int64{1, 2, 4, 10, 11, 12},
+			Values:     []float64{21, 22, 23, 24, 25, 26},
+		},
+	}, 5, &Result{
+		Timestamps: []int64{5, 10, 12},
+		Values:     []float64{7, 24, 26},
+	})
+}
diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index b251c5e2f7..77561e1d10 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -39,6 +39,7 @@ scrape_configs:
 
 * FEATURE: [query tracing](https://docs.victoriametrics.com/Single-server-VictoriaMetrics.html#query-tracing): show timestamps in query traces in human-readable format (aka `RFC3339` in UTC timezone) instead of milliseconds since Unix epoch. For example, `2022-06-27T10:32:54.506Z` instead of `1656325974506`. This improves traces' readability.
 * FEATURE: improve performance of [/api/v1/series](https://prometheus.io/docs/prometheus/latest/querying/api/#finding-series-by-label-matchers) requests, which return big number of time series.
+* FEATURE: [VictoriaMetrics cluster](https://docs.victoriametrics.com/Cluster-VictoriaMetrics.html): improve query performance when [replication is enabled](https://docs.victoriametrics.com/Cluster-VictoriaMetrics.html#replication-and-data-safety).
 * FEATURE: [MetricsQL](https://docs.victoriametrics.com/MetricsQL.html): properly handle partial counter resets in [remove_resets](https://docs.victoriametrics.com/MetricsQL.html#remove_resets) function. Now `remove_resets(sum(m))` should returns the expected increasing line when some time series matching `m` disappear on the selected time range. Previously such a query would return horizontal line after the disappeared series.
 * FEATURE: expose additional histogram metrics at `http://victoriametrics:8428/metrics`, which may help understanding query workload: