diff --git a/bench/internal/random/dummy.go b/bench/internal/random/dummy.go
index 81720ca4..1d6ee945 100644
--- a/bench/internal/random/dummy.go
+++ b/bench/internal/random/dummy.go
@@ -2,6 +2,7 @@ package random
 
 import (
 	_ "embed"
+	"sync"
 	"sync/atomic"
 	"time"
 
@@ -80,20 +81,597 @@ var (
 		"つくる椅子株式会社",
 		"NextStep Cab",
 	}
+	initUserNames = []string{
+		"Collier6283",
+		"Miller6106",
+		"Goldner6682",
+		"Schneider1218",
+		"Koss7545",
+		"Wunsch6118",
+		"Bauch8259",
+		"Wiza1083",
+		"Bernier5481",
+		"Adams4772",
+		"Rogahn4930",
+		"Gibson4831",
+		"Glover5319",
+		"Cremin5648",
+		"Rosenbaum5419",
+		"Jewess8546",
+		"Schiller7773",
+		"Tillman9519",
+		"Thiel9896",
+		"Romaguera8747",
+		"Sauer4603",
+		"Little2463",
+		"Ferry5620",
+		"Fritsch7975",
+		"Doyle8365",
+		"Senger3862",
+		"Russel3117",
+		"Zemlak4077",
+		"Morissette6671",
+		"Abbott2226",
+		"Schmitt7619",
+		"Hackett5152",
+		"Spencer7557",
+		"Balistreri7654",
+		"Eichmann1785",
+		"Reinger6098",
+		"Nolan2672",
+		"Bergstrom5257",
+		"Windler8257",
+		"Hand6708",
+		"Raynor6645",
+		"Kuhic1702",
+		"Macejkovic2347",
+		"Zulauf5967",
+		"Krajcik4871",
+		"Jacobson5077",
+		"Lakin3006",
+		"Murazik9989",
+		"Prohaska7176",
+		"Mann1266",
+		"Goodwin3084",
+		"Erdman3071",
+		"Auer2313",
+		"Ullrich4666",
+		"Kuhn8857",
+		"Koepp5553",
+		"Wiza3899",
+		"Weimann9061",
+		"Deckow5697",
+		"Halvorson2535",
+		"Jacobs2488",
+		"Murray1181",
+		"Feeney5120",
+		"Cartwright7372",
+		"Corwin2152",
+		"Cronin4344",
+		"Dooley4660",
+		"Schultz3223",
+		"Hoeger4249",
+		"Bogisich8906",
+		"Doyle4203",
+		"Braun7047",
+		"Yost1620",
+		"Stokes2393",
+		"Kutch2871",
+		"Wisoky6211",
+		"Terry2158",
+		"Streich5370",
+		"Balistreri7246",
+		"Jenkins7756",
+		"Gleason2560",
+		"Senger3713",
+		"Halvorson2846",
+		"Homenick4802",
+		"Rice8065",
+		"Stracke2049",
+		"Hickle5897",
+		"Greenholt2897",
+		"Batz8239",
+		"Langosh5154",
+		"Boyer7546",
+		"Zieme8137",
+		"Jast1216",
+		"Wiza8168",
+		"Kuvalis5133",
+		"Roberts8136",
+		"Krajcik7894",
+		"Lockman8562",
+		"Leannon7085",
+		"Mohr4819",
+		"Ebert9277",
+		"Rosenbaum3219",
+		"Russel5654",
+		"Abernathy4137",
+		"Gleichner7439",
+		"McGlynn4661",
+		"Little6920",
+		"Sanford7424",
+		"Kling2472",
+		"Macejkovic2278",
+		"Lueilwitz5025",
+		"Wolf9662",
+		"Heidenreich1830",
+		"Kris5001",
+		"Casper5611",
+		"Trantow7394",
+		"Harvey8253",
+		"Ullrich8738",
+		"Smitham9637",
+		"Will8456",
+		"Cummings7629",
+		"Maggio8802",
+		"Kshlerin1997",
+		"Wolf4684",
+		"Witting9441",
+		"Prohaska3338",
+		"Wyman5446",
+		"Trantow1133",
+		"Bins2881",
+		"Hills5169",
+		"Halvorson6945",
+		"Kozey8454",
+		"Jakubowski4260",
+		"Walter7648",
+		"Effertz5087",
+		"Bartoletti6342",
+		"Koss4782",
+		"Bechtelar1131",
+		"Cummings1884",
+		"Roob5057",
+		"Doyle6312",
+		"Cartwright9750",
+		"Lakin5553",
+		"Wehner7820",
+		"Cummings3944",
+		"Stroman5930",
+		"Davis7585",
+		"Gaylord5267",
+		"Schiller5919",
+		"Fisher4181",
+		"Hammes9552",
+		"Runolfsson5109",
+		"Lindgren6160",
+		"Stanton7006",
+		"Klein8204",
+		"Kemmer9220",
+		"Jerde9599",
+		"DuBuque7600",
+		"Gleason3330",
+		"Boyer9440",
+		"Brown6024",
+		"Howell3891",
+		"Johns5380",
+		"Dooley9527",
+		"Parker7053",
+		"Collins3797",
+		"Barrows6891",
+		"Schaden1352",
+		"Christiansen5051",
+		"Howell1763",
+		"Veum7702",
+		"Powlowski5283",
+		"Kovacek5336",
+		"Hermann7125",
+		"Kilback4271",
+		"Bartell8139",
+		"McDermott1805",
+		"Veum8361",
+		"Friesen1441",
+		"Sanford3543",
+		"Schumm6090",
+		"Wolff9192",
+		"Ratke6095",
+		"Runolfsdottir2790",
+		"Carter3903",
+		"Prohaska4376",
+		"Volkman2638",
+		"Berge6221",
+		"Shields1008",
+		"Reichert6920",
+		"Anderson1090",
+		"Kihn3244",
+		"Wintheiser4782",
+		"Jakubowski9136",
+		"Wunsch3821",
+		"Abernathy5113",
+		"Volkman1416",
+		"Nienow7093",
+		"Stark1670",
+		"Schneider9905",
+		"Ziemann7487",
+		"Runolfsson8579",
+		"Kemmer6629",
+		"Stehr5980",
+		"Ward6753",
+		"Walsh9821",
+		"Renner4462",
+		"Beahan1235",
+		"Kohler1110",
+		"Wilderman3936",
+		"Anderson3981",
+		"Kunze3687",
+		"Corkery5627",
+		"Mosciski7148",
+		"Altenwerth9596",
+		"Cremin3942",
+		"Heller2920",
+		"Buckridge4285",
+		"Reichel5791",
+		"Langworth6501",
+		"Gleichner7825",
+		"Donnelly6407",
+		"Steuber6876",
+		"Fisher6400",
+		"Kautzer7315",
+		"McCullough4848",
+		"Schuppe8300",
+		"Monahan6447",
+		"Jast4329",
+		"Barrows1212",
+		"Torp8836",
+		"Bechtelar6897",
+		"Hodkiewicz6351",
+		"Quitzon1924",
+		"Stanton5063",
+		"Feest1591",
+		"Adams7206",
+		"Connelly9751",
+		"Rempel8556",
+		"Halvorson2065",
+		"Rice1956",
+		"Bernhard7282",
+		"Stokes5209",
+		"Heidenreich7455",
+		"Hauck8080",
+		"Erdman4090",
+		"Schuppe1782",
+		"Carter9215",
+		"Hegmann9436",
+		"Ryan6874",
+		"Weber8236",
+		"Block1060",
+		"Parker2255",
+		"Shields5143",
+		"Nienow7148",
+		"Luettgen1997",
+		"Williamson5172",
+		"Pouros8369",
+		"Gulgowski2603",
+		"Cummerata3270",
+		"Tromp1598",
+		"Turner4332",
+		"Block5589",
+		"Will7474",
+		"Torphy8719",
+		"Hodkiewicz6336",
+		"Murphy6232",
+		"Kshlerin3787",
+		"Mueller5752",
+		"Dibbert7357",
+		"Macejkovic7933",
+		"Mohr4243",
+		"Schmidt9799",
+		"Hayes2587",
+		"Hettinger8352",
+		"Tremblay5655",
+		"Wintheiser3149",
+		"Wolf4388",
+		"Breitenberg6231",
+		"Shanahan5781",
+		"King2382",
+		"Welch3489",
+		"Thompson3912",
+		"Metz3384",
+		"Eichmann5653",
+		"Blick5768",
+		"Skiles7569",
+		"Russel7699",
+		"Kirlin2357",
+		"Huels8787",
+		"Wolf2029",
+		"Reichel3778",
+		"Waters5550",
+		"Robel2182",
+		"Koss2182",
+		"Crist3541",
+		"Tillman5701",
+		"Pfeffer2953",
+		"Treutel9469",
+		"Larson4952",
+		"Blanda9887",
+		"Dietrich6258",
+		"Kiehn5940",
+		"Waelchi6294",
+		"Fritsch8820",
+		"Bode2648",
+		"Davis9341",
+		"Kozey5568",
+		"Lind9497",
+		"OReilly2933",
+		"Kuhlman9922",
+		"Lesch1677",
+		"West3697",
+		"Emard2039",
+		"Prohaska6722",
+		"Jacobi4777",
+		"Koss7664",
+		"Corkery9615",
+		"Windler1387",
+		"Lockman8598",
+		"Torp6467",
+		"Rempel3517",
+		"Purdy8359",
+		"Hintz3967",
+		"Miller9559",
+		"Beatty1816",
+		"Medhurst9621",
+		"Gerhold8674",
+		"Gibson2468",
+		"Bogan8115",
+		"Schimmel2769",
+		"Turner7474",
+		"Vandervort2098",
+		"Osinski4696",
+		"Jenkins7731",
+		"Schmidt7552",
+		"Dietrich1502",
+		"Upton3519",
+		"Macejkovic7899",
+		"Schamberger8807",
+		"Huels7842",
+		"Green4987",
+		"Ziemann9990",
+		"Kunze8674",
+		"Donnelly5644",
+		"Williamson4000",
+		"Altenwerth5515",
+		"Keeling3408",
+		"Bins1454",
+		"Carter8722",
+		"Turner7832",
+		"Anderson4239",
+		"Sanford9746",
+		"Purdy9879",
+		"Homenick5224",
+		"Klein7281",
+		"Rau5591",
+		"Collins1124",
+		"Bosco7299",
+		"Weissnat2052",
+		"Ritchie3987",
+		"Jakubowski8194",
+		"Hoppe8034",
+		"OReilly1709",
+		"Barrows7645",
+		"Hamill2625",
+		"Hoeger7373",
+		"Wiegand7924",
+		"Lind8390",
+		"Robel8939",
+		"Hyatt7688",
+		"Parisian2382",
+		"Blanda9133",
+		"Hammes2591",
+		"Daniel8824",
+		"Johns6801",
+		"Corwin7170",
+		"Dooley4990",
+		"Leuschke1772",
+		"Anderson1749",
+		"Walsh8420",
+		"Greenfelder4904",
+		"Kessler3776",
+		"Shields9689",
+		"Harvey6562",
+		"Weimann4458",
+		"Cronin6978",
+		"Jast9794",
+		"Schuster7350",
+		"Ledner4480",
+		"Will5276",
+		"Wyman6817",
+		"Rohan4095",
+		"King2281",
+		"Jacobson2422",
+		"Luettgen2999",
+		"Kunze5330",
+		"Tillman7031",
+		"Runolfsdottir4921",
+		"Nitzsche9154",
+		"Stiedemann3406",
+		"Cronin8266",
+		"Wolff5267",
+		"Klein9118",
+		"Morar3927",
+		"Murazik5554",
+		"Wuckert8083",
+		"Hudson9208",
+		"Langosh7217",
+		"Jacobson1446",
+		"Schmitt5903",
+		"Rogahn3437",
+		"Nienow4669",
+		"Douglas2194",
+		"Watsica6995",
+		"Wehner2903",
+		"Stehr8370",
+		"Labadie7286",
+		"Green2950",
+		"Cummings3575",
+		"Hoppe4439",
+		"Wilkinson1380",
+		"Bailey3812",
+		"Shanahan8057",
+		"Kozey7719",
+		"Fadel8373",
+		"Cormier4608",
+		"Rempel2823",
+		"King7609",
+		"Walsh4192",
+		"Mraz1324",
+		"Mraz5771",
+		"Emard3819",
+		"Watsica8147",
+		"Parker5679",
+		"Hudson7173",
+		"Bruen2177",
+		"Dibbert9800",
+		"Crist2742",
+		"Steuber6440",
+		"Glover5488",
+		"Corwin2819",
+		"Christiansen9735",
+		"Keebler8881",
+		"Gutmann1571",
+		"Ankunding4137",
+		"Lynch6320",
+		"Rutherford3938",
+		"Weber1923",
+		"Wiza4742",
+		"Ankunding9610",
+		"Mraz6953",
+		"Christiansen4038",
+		"Conroy3198",
+		"Metz6655",
+		"Cartwright8204",
+		"Mueller6331",
+		"Welch4315",
+		"Rau2700",
+		"Hermann6649",
+		"Runolfsdottir6120",
+		"Parisian5363",
+		"Nader7660",
+		"Bednar6119",
+		"Schmitt3718",
+		"Ritchie5206",
+		"Hintz4622",
+		"Dach7108",
+		"Romaguera6419",
+		"Hartmann4500",
+		"Grady8253",
+		"Runolfsdottir5606",
+		"Reynolds3886",
+		"Robel5492",
+		"Schowalter5252",
+		"Weber6066",
+		"Fahey7255",
+		"Walter6040",
+		"Gislason5863",
+		"Wolff6851",
+		"Smith7438",
+		"Bechtelar8072",
+		"Rosenbaum7526",
+		"Raynor5198",
+		"Dare3839",
+		"Koss1229",
+		"Cremin2470",
+		"Treutel2907",
+		"Boyle4856",
+		"Corkery8640",
+		"Bartoletti9145",
+		"Herzog2157",
+		"Kertzmann3715",
+		"Wintheiser1479",
+		"Price6118",
+		"Walker2337",
+		"Kiehn6869",
+		"Durgan8266",
+		"Runte2488",
+		"Spencer8383",
+		"Renner2829",
+		"Kovacek8011",
+		"Turner1079",
+		"Goodwin2214",
+		"Reichert9156",
+		"Mayer3472",
+		"Lang4780",
+		"Lemke1333",
+		"Mosciski1314",
+		"Ankunding6481",
+		"Rolfson3528",
+		"Beahan9753",
+		"Kunde8814",
+		"Weimann5879",
+		"Kilback9778",
+		"Hartmann5809",
+		"Moore5847",
+		"Kling1466",
+		"Abbott3770",
+		"Conroy4167",
+		"Kuhlman4362",
+		"Aufderhar3256",
+		"Torp2074",
+		"Sauer4924",
+		"Turner4286",
+		"Hoppe5969",
+		"Gislason8371",
+		"Robel2343",
+		"Bailey8827",
+		"Mohr6261",
+		"Pagac3569",
+		"Little2009",
+		"Pagac8849",
+		"Wehner3146",
+		"Prosacco4476",
+		"Marquardt7924",
+		"Padberg8567",
+		"Carroll4063",
+		"Kassulke4811",
+		"Walter6041",
+		"Cole6086",
+		"Huels8350",
+		"Friesen6579",
+		"Mosciski8695",
+		"Schuster2212",
+		"Langosh7516",
+		"Hilll5876",
+		"Fadel5143",
+		"Lebsack9517",
+		"Runolfsson8332",
+		"Robel8055",
+		"Blanda7940",
+		"Ebert9987",
+		"Glover2890",
+		"Gottlieb5723",
+		"Oberbrunner6603",
+		"Muller6146",
+		"Trantow1326",
+		"Jast9376",
+	}
+	usedUserNames     = map[string]struct{}{}
+	usedUserNamesLock sync.Mutex
 )
 
 func init() {
 	// 内部データをロードさせておく
 	_ = gimei.NewName()
 	ownerNames = lo.Shuffle(lo.Filter(ownerNames, func(name string, _ int) bool { return !lo.Contains(initOwnerNames, name) }))
+	for _, name := range initUserNames {
+		usedUserNames[name] = struct{}{}
+	}
 }
 
 func GenerateOwnerName() string {
 	return ownerNames[int(ownerNamesIdx.Add(1))%len(ownerNames)]
 }
-func GenerateLastName() string     { return gimei.NewName().Last.Kanji() }
-func GenerateFirstName() string    { return gimei.NewName().First.Kanji() }
-func GenerateUserName() string     { return gofakeit.Username() }
+func GenerateLastName() string  { return gimei.NewName().Last.Kanji() }
+func GenerateFirstName() string { return gimei.NewName().First.Kanji() }
+func GenerateUserName() string {
+	usedUserNamesLock.Lock()
+	defer usedUserNamesLock.Unlock()
+	for {
+		s := gofakeit.Username()
+		if _, ok := usedUserNames[s]; ok {
+			continue
+		}
+		usedUserNames[s] = struct{}{}
+		return s
+	}
+}
 func GenerateDateOfBirth() string  { return gofakeit.DateRange(dateStart, dateEnd).Format("2006-01-02") }
 func GeneratePaymentToken() string { return gofakeit.LetterN(100) }
 func GenerateHexString(n int) string {