From 6bf9b48ac3349630c96be8fe20e75089515af8e4 Mon Sep 17 00:00:00 2001
From: sokovykh-md <sokovykh.work@gmail.com>
Date: Sun, 19 Apr 2026 16:17:48 +0300
Subject: [PATCH] Add repeats aggregation to stabilize latency metrics

---
 example/pgcompare.yaml                   |  1 +
 example/report.html                      | 43 +++++++------
 internal/pgcompare/bench.go              | 80 ++++++++++++++++++++++++
 internal/pgcompare/config.go             |  7 +++
 internal/pgcompare/config_test.go        |  1 +
 internal/pgcompare/model.go              |  1 +
 internal/pgcompare/templates/report.html |  5 +-
 main.go                                  |  7 ++-
 8 files changed, 122 insertions(+), 23 deletions(-)

diff --git a/example/pgcompare.yaml b/example/pgcompare.yaml
index 6b54e05..1802527 100644
--- a/example/pgcompare.yaml
+++ b/example/pgcompare.yaml
@@ -11,6 +11,7 @@ benchmark:
   warmup_iterations: 5
   iterations: 1000
   concurrency: 1
+  repeats: 3
 
 report:
   description:
diff --git a/example/report.html b/example/report.html
index b4c04dd..f4a0bc4 100644
--- a/example/report.html
+++ b/example/report.html
@@ -118,27 +118,27 @@
 <div class="main" id="app"></div>
 
 <script>
-     
+
     window.reportData = (function() {
         var beforeStats = [];
-        beforeStats.push({QueryName:"top_rated_blocked_drivers",Min: 549 ,Max: 6672 ,P50: 615 ,P95: 695 ,P99: 996 ,Mean: 640 ,StdDev: 251 ,QPS: 1561.6662971269682 ,ErrorRate: 0 });
-        beforeStats.push({QueryName:"latest_ride_status",Min: 2408 ,Max: 7770 ,P50: 2914 ,P95: 5089 ,P99: 6293 ,Mean: 3238 ,StdDev: 829 ,QPS: 308.7508560121342 ,ErrorRate: 0 });
-        beforeStats.push({QueryName:"failed_payments_by_amount",Min: 1295 ,Max: 2995 ,P50: 1394 ,P95: 1508 ,P99: 1940 ,Mean: 1412 ,StdDev: 120 ,QPS: 707.9192653672029 ,ErrorRate: 0 });
-        beforeStats.push({QueryName:"top_final_fare_quotes",Min: 1330 ,Max: 2509 ,P50: 1432 ,P95: 1512 ,P99: 1605 ,Mean: 1439 ,StdDev: 57 ,QPS: 694.4478805146866 ,ErrorRate: 0 });
-        beforeStats.push({QueryName:"pickup_stops_with_coordinates",Min: 260 ,Max: 2435 ,P50: 305 ,P95: 341 ,P99: 613 ,Mean: 317 ,StdDev: 107 ,QPS: 3148.460130811655 ,ErrorRate: 0 });
+        beforeStats.push({QueryName:"top_rated_blocked_drivers",Min: 506 ,Max: 881 ,P50: 552 ,P95: 592 ,P99: 679 ,Mean: 555 ,StdDev: 23 ,QPS: 1799.9548211339893 ,ErrorRate: 0 });
+        beforeStats.push({QueryName:"latest_ride_status",Min: 2261 ,Max: 11186 ,P50: 2426 ,P95: 3347 ,P99: 3664 ,Mean: 2625 ,StdDev: 470 ,QPS: 380.8231669989785 ,ErrorRate: 0 });
+        beforeStats.push({QueryName:"failed_payments_by_amount",Min: 1215 ,Max: 4180 ,P50: 1327 ,P95: 1401 ,P99: 1643 ,Mean: 1343 ,StdDev: 161 ,QPS: 743.9306879778011 ,ErrorRate: 0 });
+        beforeStats.push({QueryName:"top_final_fare_quotes",Min: 1273 ,Max: 4524 ,P50: 1369 ,P95: 1424 ,P99: 1626 ,Mean: 1386 ,StdDev: 178 ,QPS: 721.0890608085392 ,ErrorRate: 0 });
+        beforeStats.push({QueryName:"pickup_stops_with_coordinates",Min: 178 ,Max: 734 ,P50: 212 ,P95: 245 ,P99: 260 ,Mean: 214 ,StdDev: 30 ,QPS: 4661.217839741066 ,ErrorRate: 0 });
         var afterStats = [];
-        afterStats.push({QueryName:"top_rated_blocked_drivers",Min: 100 ,Max: 259 ,P50: 124 ,P95: 157 ,P99: 186 ,Mean: 127 ,StdDev: 16 ,QPS: 7807.168131120951 ,ErrorRate: 0 });
-        afterStats.push({QueryName:"latest_ride_status",Min: 2512 ,Max: 5229 ,P50: 2677 ,P95: 3009 ,P99: 3272 ,Mean: 2719 ,StdDev: 176 ,QPS: 367.7598542861905 ,ErrorRate: 0 });
-        afterStats.push({QueryName:"failed_payments_by_amount",Min: 156 ,Max: 1695 ,P50: 199 ,P95: 272 ,P99: 751 ,Mean: 217 ,StdDev: 112 ,QPS: 4591.693251307876 ,ErrorRate: 0 });
-        afterStats.push({QueryName:"top_final_fare_quotes",Min: 80 ,Max: 275 ,P50: 117 ,P95: 136 ,P99: 154 ,Mean: 117 ,StdDev: 13 ,QPS: 8482.049028262112 ,ErrorRate: 0 });
-        afterStats.push({QueryName:"pickup_stops_with_coordinates",Min: 151 ,Max: 505 ,P50: 188 ,P95: 210 ,P99: 235 ,Mean: 190 ,StdDev: 16 ,QPS: 5259.237686645415 ,ErrorRate: 0 });
+        afterStats.push({QueryName:"top_rated_blocked_drivers",Min: 82 ,Max: 240 ,P50: 117 ,P95: 131 ,P99: 143 ,Mean: 117 ,StdDev: 11 ,QPS: 8487.898531450957 ,ErrorRate: 0 });
+        afterStats.push({QueryName:"latest_ride_status",Min: 2514 ,Max: 11479 ,P50: 2674 ,P95: 3916 ,P99: 6610 ,Mean: 2914 ,StdDev: 775 ,QPS: 343.0814985917741 ,ErrorRate: 0 });
+        afterStats.push({QueryName:"failed_payments_by_amount",Min: 176 ,Max: 1761 ,P50: 203 ,P95: 359 ,P99: 635 ,Mean: 231 ,StdDev: 94 ,QPS: 4319.222971787375 ,ErrorRate: 0 });
+        afterStats.push({QueryName:"top_final_fare_quotes",Min: 89 ,Max: 349 ,P50: 117 ,P95: 132 ,P99: 154 ,Mean: 118 ,StdDev: 13 ,QPS: 8405.2212999369 ,ErrorRate: 0 });
+        afterStats.push({QueryName:"pickup_stops_with_coordinates",Min: 158 ,Max: 2362 ,P50: 187 ,P95: 221 ,P99: 295 ,Mean: 198 ,StdDev: 124 ,QPS: 5041.666220269137 ,ErrorRate: 0 });
         var diffs = [];
-        diffs.push({QueryName:"top_rated_blocked_drivers",Summary:["Sort -\u003e Nested Loop","Explicit Sort removed","Merge Join -\u003e Index Scan on drivers","Index added: idx_drivers_status_rating","Actual rows changed: 294 -\u003e 10",],BeforeText:"-\u003e Limit (rows=10 time=731µs)\n  -\u003e Sort (rows=10 time=731µs)\n    -\u003e Merge Join (rows=294 time=704µs)\n      -\u003e Index Scan on users using users_pkey (rows=4999 time=283µs)\n      -\u003e Sort (rows=294 time=277µs)\n        -\u003e Seq Scan on drivers (rows=294 time=250µs)\n",AfterText:"-\u003e Limit (rows=10 time=24µs)\n  -\u003e Nested Loop (rows=10 time=24µs)\n    -\u003e Index Scan on drivers using idx_drivers_status_rating (rows=10 time=9µs)\n    -\u003e Index Scan on users using users_pkey (rows=1 time=1µs)\n"});
-        diffs.push({QueryName:"latest_ride_status",Summary:["Unique -\u003e Result","Sort -\u003e Unique","Explicit Sort removed","Seq Scan -\u003e Index Only Scan on ride_status_events","Index added: idx_ride_status_events_ride_created_id",],BeforeText:"-\u003e Unique (rows=10000 time=1.523ms)\n  -\u003e Sort (rows=10000 time=1.065ms)\n    -\u003e Seq Scan on ride_status_events (rows=10000 time=457µs)\n",AfterText:"-\u003e Result (rows=10000 time=1.8ms)\n  -\u003e Unique (rows=10000 time=1.349ms)\n    -\u003e Index Only Scan on ride_status_events using idx_ride_status_events_ride_created_id (rows=10000 time=743µs)\n"});
-        diffs.push({QueryName:"failed_payments_by_amount",Summary:["Sort -\u003e Nested Loop","Explicit Sort removed","Merge Join -\u003e Index Scan on payments","Index added: idx_payments_status_amount","Actual rows changed: 2000 -\u003e 100",],BeforeText:"-\u003e Limit (rows=100 time=1.623ms)\n  -\u003e Sort (rows=100 time=1.619ms)\n    -\u003e Merge Join (rows=2000 time=1.45ms)\n      -\u003e Index Scan on payment_methods using payment_methods_pkey (rows=10001 time=525µs)\n      -\u003e Sort (rows=2000 time=476µs)\n        -\u003e Seq Scan on payments (rows=2000 time=347µs)\n",AfterText:"-\u003e Limit (rows=100 time=150µs)\n  -\u003e Nested Loop (rows=100 time=147µs)\n    -\u003e Index Scan on payments using idx_payments_status_amount (rows=100 time=52µs)\n    -\u003e Index Scan on payment_methods using payment_methods_pkey (rows=1 time=1µs)\n"});
-        diffs.push({QueryName:"top_final_fare_quotes",Summary:["Sort -\u003e Nested Loop","Explicit Sort removed","Hash Join -\u003e Index Only Scan on ride_fare_quotes","Index added: idx_rfq_kind_amount","Actual rows changed: 5000 -\u003e 10",],BeforeText:"-\u003e Limit (rows=10 time=1.806ms)\n  -\u003e Sort (rows=10 time=1.806ms)\n    -\u003e Hash Join (rows=5000 time=1.532ms)\n      -\u003e Seq Scan on ride_fare_quotes (rows=5000 time=353µs)\n      -\u003e Hash (rows=10000 time=805µs)\n        -\u003e Seq Scan on rides (rows=10000 time=404µs)\n",AfterText:"-\u003e Limit (rows=10 time=16µs)\n  -\u003e Nested Loop (rows=10 time=15µs)\n    -\u003e Index Only Scan on ride_fare_quotes using idx_rfq_kind_amount (rows=10 time=7µs)\n    -\u003e Index Scan on rides using rides_pkey (rows=1 time=1µs)\n"});
-        diffs.push({QueryName:"pickup_stops_with_coordinates",Summary:["Index Scan -\u003e Index Only Scan on ride_stops","Index changed: uq_ride_stops_ride_stop_index -\u003e idx_ride_stops_pickup_ride",],BeforeText:"-\u003e Limit (rows=100 time=57µs)\n  -\u003e Nested Loop (rows=100 time=54µs)\n    -\u003e Index Scan on ride_stops using uq_ride_stops_ride_stop_index (rows=100 time=16µs)\n    -\u003e Index Scan on addresses using addresses_pkey (rows=1 time=0s)\n",AfterText:"-\u003e Limit (rows=100 time=49µs)\n  -\u003e Nested Loop (rows=100 time=46µs)\n    -\u003e Index Only Scan on ride_stops using idx_ride_stops_pickup_ride (rows=100 time=8µs)\n    -\u003e Index Scan on addresses using addresses_pkey (rows=1 time=0s)\n"});
-        var speedups = [ 4.421473574457534 , 1.6912832696461206 , 5.531711574284583 , 11.087384051329057 , 1.6215895610913404 ,];
+        diffs.push({QueryName:"top_rated_blocked_drivers",Summary:["Sort -\u003e Nested Loop","Explicit Sort removed","Merge Join -\u003e Index Scan on drivers","Index added: idx_drivers_status_rating","Actual rows changed: 294 -\u003e 10",],BeforeText:"-\u003e Limit (rows=10 time=601µs)\n  -\u003e Sort (rows=10 time=601µs)\n    -\u003e Merge Join (rows=294 time=576µs)\n      -\u003e Index Scan on users using users_pkey (rows=4999 time=261µs)\n      -\u003e Sort (rows=294 time=154µs)\n        -\u003e Seq Scan on drivers (rows=294 time=130µs)\n",AfterText:"-\u003e Limit (rows=10 time=34µs)\n  -\u003e Nested Loop (rows=10 time=33µs)\n    -\u003e Index Scan on drivers using idx_drivers_status_rating (rows=10 time=10µs)\n    -\u003e Index Scan on users using users_pkey (rows=1 time=2µs)\n"});
+        diffs.push({QueryName:"latest_ride_status",Summary:["Unique -\u003e Result","Sort -\u003e Unique","Explicit Sort removed","Seq Scan -\u003e Index Only Scan on ride_status_events","Index added: idx_ride_status_events_ride_created_id",],BeforeText:"-\u003e Unique (rows=10000 time=1.601ms)\n  -\u003e Sort (rows=10000 time=1.111ms)\n    -\u003e Seq Scan on ride_status_events (rows=10000 time=468µs)\n",AfterText:"-\u003e Result (rows=10000 time=1.823ms)\n  -\u003e Unique (rows=10000 time=1.377ms)\n    -\u003e Index Only Scan on ride_status_events using idx_ride_status_events_ride_created_id (rows=10000 time=771µs)\n"});
+        diffs.push({QueryName:"failed_payments_by_amount",Summary:["Sort -\u003e Nested Loop","Explicit Sort removed","Merge Join -\u003e Index Scan on payments","Index added: idx_payments_status_amount","Actual rows changed: 2000 -\u003e 100",],BeforeText:"-\u003e Limit (rows=100 time=1.722ms)\n  -\u003e Sort (rows=100 time=1.719ms)\n    -\u003e Merge Join (rows=2000 time=1.536ms)\n      -\u003e Index Scan on payment_methods using payment_methods_pkey (rows=10001 time=535µs)\n      -\u003e Sort (rows=2000 time=516µs)\n        -\u003e Seq Scan on payments (rows=2000 time=370µs)\n",AfterText:"-\u003e Limit (rows=100 time=158µs)\n  -\u003e Nested Loop (rows=100 time=154µs)\n    -\u003e Index Scan on payments using idx_payments_status_amount (rows=100 time=49µs)\n    -\u003e Index Scan on payment_methods using payment_methods_pkey (rows=1 time=1µs)\n"});
+        diffs.push({QueryName:"top_final_fare_quotes",Summary:["Sort -\u003e Nested Loop","Explicit Sort removed","Hash Join -\u003e Index Only Scan on ride_fare_quotes","Index added: idx_rfq_kind_amount","Actual rows changed: 5000 -\u003e 10",],BeforeText:"-\u003e Limit (rows=10 time=1.922ms)\n  -\u003e Sort (rows=10 time=1.922ms)\n    -\u003e Hash Join (rows=5000 time=1.63ms)\n      -\u003e Seq Scan on ride_fare_quotes (rows=5000 time=333µs)\n      -\u003e Hash (rows=10000 time=839µs)\n        -\u003e Seq Scan on rides (rows=10000 time=416µs)\n",AfterText:"-\u003e Limit (rows=10 time=20µs)\n  -\u003e Nested Loop (rows=10 time=20µs)\n    -\u003e Index Only Scan on ride_fare_quotes using idx_rfq_kind_amount (rows=10 time=8µs)\n    -\u003e Index Scan on rides using rides_pkey (rows=1 time=1µs)\n"});
+        diffs.push({QueryName:"pickup_stops_with_coordinates",Summary:["Index Scan -\u003e Index Only Scan on ride_stops","Index changed: uq_ride_stops_ride_stop_index -\u003e idx_ride_stops_pickup_ride",],BeforeText:"-\u003e Limit (rows=100 time=64µs)\n  -\u003e Nested Loop (rows=100 time=60µs)\n    -\u003e Index Scan on ride_stops using uq_ride_stops_ride_stop_index (rows=100 time=18µs)\n    -\u003e Index Scan on addresses using addresses_pkey (rows=1 time=0s)\n",AfterText:"-\u003e Limit (rows=100 time=56µs)\n  -\u003e Nested Loop (rows=100 time=52µs)\n    -\u003e Index Only Scan on ride_stops using idx_ride_stops_pickup_ride (rows=100 time=9µs)\n    -\u003e Index Scan on addresses using addresses_pkey (rows=1 time=0s)\n"});
+        var speedups = [ 4.491306161137441 , 0.854730699345197 , 3.9025264524107275 , 10.781185923869044 , 1.1070067310031628 ,];
         var description = [];
         description.push({Query:"top_rated_blocked_drivers",What:"Добавлен покрывающий индекс idx_drivers_status_rating по status и rating DESC",Changes:"\"CREATE INDEX idx_drivers_status_rating ON drivers(status, rating DESC) INCLUDE(user_id)\"",Expected:"Index Only Scan с ранним выходом при LIMIT 10 вместо Seq Scan \u002b Sort по всем заблокированным водителям"});
         description.push({Query:"latest_ride_status",What:"Добавлен покрывающий индекс idx_ride_status_events_ride_created_id под DISTINCT ON по ride_id",Changes:"\"CREATE INDEX idx_ride_status_events_ride_created_id ON ride_status_events(ride_id, created_at DESC, id DESC) INCLUDE(to_status)\"",Expected:"DISTINCT ON использует Index Only Scan без шага Sort вместо Seq Scan \u002b Sort \u002b WindowAgg"});
@@ -146,10 +146,11 @@
         description.push({Query:"top_final_fare_quotes",What:"Добавлен покрывающий индекс idx_rfq_kind_amount по kind и amount DESC",Changes:"\"CREATE INDEX idx_rfq_kind_amount ON ride_fare_quotes(kind, amount DESC) INCLUDE(ride_id)\"",Expected:"Index Only Scan с ранним выходом при LIMIT 10 вместо Seq Scan \u002b Filter \u002b Sort по 5000 строкам"});
         description.push({Query:"pickup_stops_with_coordinates",What:"Добавлены индексы idx_ride_stops_pickup_ride и idx_addresses_id_coords для выборки pickup и координат",Changes:"\"CREATE INDEX idx_ride_stops_pickup_ride ON ride_stops(ride_id) INCLUDE(address_id) WHERE kind='pickup'; CREATE INDEX idx_addresses_id_coords ON addresses(id) INCLUDE(lat, lon)\"",Expected:"Partial Index Only Scan на ride_stops с ранним выходом при LIMIT 100 вместо Seq Scan 30k строк \u002b Sort; NL join на addresses через Index Only Scan"});
         return {
-            GeneratedAt: "16.04.2026, 14:10:05",
+            GeneratedAt: "19.04.2026, 15:55:25",
             Iterations:  1000 ,
-            WarmupIterations:  5 ,
+            WarmupIterations:  50 ,
             Concurrency:  1 ,
+            Repeats:  3 ,
             Speedups: speedups,
             Description: description,
             Before: {Phase: "before", Stats: beforeStats},
@@ -195,7 +196,8 @@
     var BENCH_PARAM_HINTS = {
         'iterations': 'Количество измеряемых выполнений каждого запроса в фазах before/after.',
         'warmup iterations': 'Количество предварительных прогонов перед замером каждого запроса.',
-        'concurrency': 'Количество конкурентных воркеров, выполняющих запросы во время измерений.'
+        'concurrency': 'Количество конкурентных воркеров, выполняющих запросы во время измерений.',
+        'repeats': 'Количество независимых повторов бенчмарка на фазу. Метрики агрегируются по медиане, что гасит случайные выбросы между прогонами.'
     };
 
     function hintIconFromText(text) {
@@ -230,6 +232,7 @@
                 + buildBenchParam('iterations', data.Iterations)
                 + buildBenchParam('warmup iterations', data.WarmupIterations)
                 + buildBenchParam('concurrency', data.Concurrency)
+                + (data.Repeats && data.Repeats > 1 ? buildBenchParam('repeats', data.Repeats) : '')
                 + '</div>';
         }
         return '<div class="header">'
diff --git a/internal/pgcompare/bench.go b/internal/pgcompare/bench.go
index fa2777f..38425d9 100644
--- a/internal/pgcompare/bench.go
+++ b/internal/pgcompare/bench.go
@@ -174,6 +174,86 @@ func (b *benchmark) ValidateMatchingQueryNames(beforeQueries, afterQueries []Que
 	return nil
 }
 
+func (b *benchmark) RunRepeats(ctx context.Context, queries []Query, repeats, iterations, concurrency, warmupIterations uint) ([]Stats, error) {
+	if repeats == 0 {
+		repeats = 1
+	}
+	samples := make([][]Stats, repeats)
+	for r := uint(0); r < repeats; r++ {
+		b.log.Info("Running repeat", "repeat", r+1, "total", repeats)
+		s, err := b.Run(ctx, queries, iterations, concurrency, warmupIterations)
+		if err != nil {
+			return nil, fmt.Errorf("repeat %d: %w", r+1, err)
+		}
+		samples[r] = s
+	}
+	return aggregateRepeatStats(queries, samples), nil
+}
+
+func aggregateRepeatStats(queries []Query, samples [][]Stats) []Stats {
+	out := make([]Stats, len(queries))
+	for qi, q := range queries {
+		durs := map[string][]time.Duration{
+			"Min": nil, "Max": nil, "P50": nil, "P95": nil, "P99": nil, "Mean": nil, "StdDev": nil,
+		}
+		var qps, errRate []float64
+		var errs []string
+		for _, rep := range samples {
+			s := rep[qi]
+			durs["Min"] = append(durs["Min"], s.Min)
+			durs["Max"] = append(durs["Max"], s.Max)
+			durs["P50"] = append(durs["P50"], s.P50)
+			durs["P95"] = append(durs["P95"], s.P95)
+			durs["P99"] = append(durs["P99"], s.P99)
+			durs["Mean"] = append(durs["Mean"], s.Mean)
+			durs["StdDev"] = append(durs["StdDev"], s.StdDev)
+			qps = append(qps, s.QPS)
+			errRate = append(errRate, s.ErrorRate)
+			errs = append(errs, s.Errors...)
+		}
+		out[qi] = Stats{
+			QueryName: q.Name,
+			Min:       medianDuration(durs["Min"]),
+			Max:       medianDuration(durs["Max"]),
+			P50:       medianDuration(durs["P50"]),
+			P95:       medianDuration(durs["P95"]),
+			P99:       medianDuration(durs["P99"]),
+			Mean:      medianDuration(durs["Mean"]),
+			StdDev:    medianDuration(durs["StdDev"]),
+			QPS:       medianFloat64(qps),
+			ErrorRate: medianFloat64(errRate),
+			Errors:    errs,
+		}
+	}
+	return out
+}
+
+func medianDuration(values []time.Duration) time.Duration {
+	if len(values) == 0 {
+		return 0
+	}
+	cp := append([]time.Duration(nil), values...)
+	sort.Slice(cp, func(i, j int) bool { return cp[i] < cp[j] })
+	n := len(cp)
+	if n%2 == 1 {
+		return cp[n/2]
+	}
+	return (cp[n/2-1] + cp[n/2]) / 2
+}
+
+func medianFloat64(values []float64) float64 {
+	if len(values) == 0 {
+		return 0
+	}
+	cp := append([]float64(nil), values...)
+	sort.Float64s(cp)
+	n := len(cp)
+	if n%2 == 1 {
+		return cp[n/2]
+	}
+	return (cp[n/2-1] + cp[n/2]) / 2
+}
+
 func (b *benchmark) Run(ctx context.Context, queries []Query, iterations, concurrency, warmupIterations uint) ([]Stats, error) {
 	b.log.Info("Running queries", "queries", queries, "iterations", iterations, "warmup_iterations", warmupIterations)
 
diff --git a/internal/pgcompare/config.go b/internal/pgcompare/config.go
index 7c426a2..dbf7a6b 100644
--- a/internal/pgcompare/config.go
+++ b/internal/pgcompare/config.go
@@ -36,6 +36,7 @@ type Config struct {
 		WarmupIterations int    `yaml:"warmup_iterations" default:"0"`
 		Iterations       int    `yaml:"iterations"`
 		Concurrency      int    `yaml:"concurrency"`
+		Repeats          int    `yaml:"repeats"`
 	} `yaml:"benchmark"`
 
 	Report struct {
@@ -65,6 +66,9 @@ func LoadConfig(configPath string) (*Config, error) {
 
 	cfg.ProjectDir = projectDir
 	cfg.Migration.EnvVar = normalizeMigrationEnvVar(cfg.Migration.EnvVar)
+	if cfg.Benchmark.Repeats == 0 {
+		cfg.Benchmark.Repeats = 1
+	}
 
 	if err := godotenv.Load(filepath.Join(projectDir, ".env")); err != nil {
 		return nil, fmt.Errorf("load .env: %w", err)
@@ -115,6 +119,9 @@ func (c *Config) validate() error {
 	if c.Benchmark.Concurrency <= 0 {
 		return fmt.Errorf("benchmark.concurrency must be positive")
 	}
+	if c.Benchmark.Repeats <= 0 {
+		return fmt.Errorf("benchmark.repeats must be positive")
+	}
 	return nil
 }
 
diff --git a/internal/pgcompare/config_test.go b/internal/pgcompare/config_test.go
index ef11f1e..3e5e9be 100644
--- a/internal/pgcompare/config_test.go
+++ b/internal/pgcompare/config_test.go
@@ -236,6 +236,7 @@ func validConfigForTest() Config {
 	cfg.Benchmark.WarmupIterations = 0
 	cfg.Benchmark.Iterations = 10
 	cfg.Benchmark.Concurrency = 2
+	cfg.Benchmark.Repeats = 1
 	return cfg
 }
 
diff --git a/internal/pgcompare/model.go b/internal/pgcompare/model.go
index 0eb938d..ce5113f 100644
--- a/internal/pgcompare/model.go
+++ b/internal/pgcompare/model.go
@@ -42,6 +42,7 @@ type ReportData struct {
 	Iterations       int
 	WarmupIterations int
 	Concurrency      int
+	Repeats          int
 	Speedups         []float64
 	Before           *BenchResult
 	After            *BenchResult
diff --git a/internal/pgcompare/templates/report.html b/internal/pgcompare/templates/report.html
index 3484b83..9a2ad64 100644
--- a/internal/pgcompare/templates/report.html
+++ b/internal/pgcompare/templates/report.html
@@ -134,6 +134,7 @@
             Iterations: {{ .Iterations }},
             WarmupIterations: {{ .WarmupIterations }},
             Concurrency: {{ .Concurrency }},
+            Repeats: {{ .Repeats }},
             Speedups: speedups,
             Description: description,
             Before: {Phase: "{{ .Before.Phase }}", Stats: beforeStats},
@@ -179,7 +180,8 @@
     var BENCH_PARAM_HINTS = {
         'iterations': 'Количество измеряемых выполнений каждого запроса в фазах before/after.',
         'warmup iterations': 'Количество предварительных прогонов перед замером каждого запроса.',
-        'concurrency': 'Количество конкурентных воркеров, выполняющих запросы во время измерений.'
+        'concurrency': 'Количество конкурентных воркеров, выполняющих запросы во время измерений.',
+        'repeats': 'Количество независимых повторов бенчмарка на фазу. Метрики агрегируются по медиане, что гасит случайные выбросы между прогонами.'
     };
 
     function hintIconFromText(text) {
@@ -214,6 +216,7 @@
                 + buildBenchParam('iterations', data.Iterations)
                 + buildBenchParam('warmup iterations', data.WarmupIterations)
                 + buildBenchParam('concurrency', data.Concurrency)
+                + (data.Repeats && data.Repeats > 1 ? buildBenchParam('repeats', data.Repeats) : '')
                 + '</div>';
         }
         return '<div class="header">'
diff --git a/main.go b/main.go
index 06877eb..d43ef34 100644
--- a/main.go
+++ b/main.go
@@ -108,9 +108,10 @@ func runBenchmark(_ *cobra.Command, _ []string) error {
 	}
 
 	fmt.Fprintln(os.Stderr, "Benchmarking 'before'...")
-	beforeStats, err := bench.Run(
+	beforeStats, err := bench.RunRepeats(
 		ctx,
 		beforeQueries,
+		uint(cfg.Benchmark.Repeats),
 		uint(cfg.Benchmark.Iterations),
 		uint(cfg.Benchmark.Concurrency),
 		uint(cfg.Benchmark.WarmupIterations),
@@ -133,9 +134,10 @@ func runBenchmark(_ *cobra.Command, _ []string) error {
 	}
 
 	fmt.Fprintln(os.Stderr, "Benchmarking 'after'...")
-	afterStats, err := bench.Run(
+	afterStats, err := bench.RunRepeats(
 		ctx,
 		afterQueries,
+		uint(cfg.Benchmark.Repeats),
 		uint(cfg.Benchmark.Iterations),
 		uint(cfg.Benchmark.Concurrency),
 		uint(cfg.Benchmark.WarmupIterations),
@@ -166,6 +168,7 @@ func runBenchmark(_ *cobra.Command, _ []string) error {
 		Iterations:       cfg.Benchmark.Iterations,
 		WarmupIterations: cfg.Benchmark.WarmupIterations,
 		Concurrency:      cfg.Benchmark.Concurrency,
+		Repeats:          cfg.Benchmark.Repeats,
 		Speedups:         speedups,
 		Before: &pgcompare.BenchResult{
 			Phase: "before",