Duplicate trial numbers are assigned on parallel execution.

[c-bata]

Refs: optuna/optuna#1488

The same problem is exist on Goptuna.

[c-bata]

Optuna resolved this issue by using SELECT ... FOR UPDATE.

optuna/optuna#1490

[c-bata]

Before

package main

import (
	"context"
	"flag"
	"log"
	"math"

	"github.com/c-bata/goptuna"
	"github.com/c-bata/goptuna/rdb"
	"github.com/c-bata/goptuna/tpe"
	"github.com/jinzhu/gorm"
	_ "github.com/jinzhu/gorm/dialects/mysql"
	_ "github.com/jinzhu/gorm/dialects/sqlite"
	"golang.org/x/sync/errgroup"
)

func objective(trial goptuna.Trial) (float64, error) {
	x1, _ := trial.SuggestFloat("x1", -10, 10)
	x2, _ := trial.SuggestFloat("x2", -10, 10)
	return math.Pow(x1-2, 2) + math.Pow(x2+5, 2), nil
}

func main() {
	flag.Parse()
	if len(flag.Args()) == 0 {
		log.Fatal("please pass dialect and dsn")
	}
	dialect := flag.Arg(0)
	dsn := flag.Arg(1)

	db, err := gorm.Open(dialect, dsn)
	if err != nil {
		log.Fatal("failed to open db:", err)
	}

	rdb.RunAutoMigrate(db)
	storage := rdb.NewStorage(db)
	defer db.Close()

	study, err := goptuna.CreateStudy(
		"rdb",
		goptuna.StudyOptionStorage(storage),
		goptuna.StudyOptionSampler(tpe.NewSampler()),
		goptuna.StudyOptionDirection(goptuna.StudyDirectionMinimize),
		goptuna.StudyOptionLoadIfExists(true),
	)
	if err != nil {
		log.Fatal("failed to create study", err)
	}

	eg, ctx := errgroup.WithContext(context.Background())
	study.WithContext(ctx)
	for i := 0; i < 10; i++ {
		eg.Go(func() error {
			return study.Optimize(objective, 20)
		})
	}
	if err := eg.Wait(); err != nil {
		log.Fatal("Optimize error", err)
	}

	trials, err := study.GetTrials()
	if err != nil {
		log.Fatal("failed to get trials", err)
	}
	for i := range trials {
		log.Printf("trial id=%d: number=%d\n", trials[i].ID, trials[i].Number)
	}

	v, err := study.GetBestValue()
	if err != nil {
		log.Fatal("failed to get best value", err)
	}
	params, err := study.GetBestParams()
	if err != nil {
		log.Fatal("failed to get best params:", err)
	}
	log.Printf("Best evaluation=%f (x1=%f, x2=%f)",
		v, params["x1"].(float64), params["x2"].(float64))
}

2020/10/29 01:39:30 trial id=1: number=0
2020/10/29 01:39:30 trial id=2: number=1
2020/10/29 01:39:30 trial id=3: number=1
2020/10/29 01:39:30 trial id=4: number=1
2020/10/29 01:39:30 trial id=5: number=1
2020/10/29 01:39:30 trial id=6: number=1
2020/10/29 01:39:30 trial id=7: number=1
2020/10/29 01:39:30 trial id=8: number=1
2020/10/29 01:39:30 trial id=9: number=4
2020/10/29 01:39:30 trial id=10: number=5
2020/10/29 01:39:30 trial id=11: number=10
2020/10/29 01:39:30 trial id=12: number=11
2020/10/29 01:39:30 trial id=13: number=12
2020/10/29 01:39:30 trial id=14: number=13
2020/10/29 01:39:30 trial id=15: number=14
2020/10/29 01:39:30 trial id=16: number=15
2020/10/29 01:39:30 trial id=17: number=16
2020/10/29 01:39:30 trial id=18: number=17
2020/10/29 01:39:30 trial id=19: number=17
2020/10/29 01:39:30 trial id=20: number=19
2020/10/29 01:39:30 trial id=21: number=20
2020/10/29 01:39:30 trial id=22: number=21
2020/10/29 01:39:30 trial id=23: number=22
2020/10/29 01:39:30 trial id=24: number=23
2020/10/29 01:39:30 trial id=25: number=24
2020/10/29 01:39:30 trial id=26: number=25
2020/10/29 01:39:30 trial id=27: number=26
2020/10/29 01:39:30 trial id=28: number=26
2020/10/29 01:39:30 trial id=29: number=28
2020/10/29 01:39:30 trial id=30: number=29
2020/10/29 01:39:30 trial id=31: number=30
2020/10/29 01:39:30 trial id=32: number=31
2020/10/29 01:39:30 trial id=33: number=32
2020/10/29 01:39:30 trial id=34: number=33
2020/10/29 01:39:30 trial id=35: number=34
2020/10/29 01:39:30 trial id=36: number=35
2020/10/29 01:39:30 trial id=37: number=35
2020/10/29 01:39:30 trial id=38: number=37
2020/10/29 01:39:30 trial id=39: number=38
2020/10/29 01:39:30 trial id=40: number=39
2020/10/29 01:39:30 trial id=41: number=40
2020/10/29 01:39:30 trial id=42: number=41
2020/10/29 01:39:30 trial id=43: number=42
2020/10/29 01:39:30 trial id=44: number=43
2020/10/29 01:39:30 trial id=45: number=44
2020/10/29 01:39:30 trial id=46: number=45
2020/10/29 01:39:30 trial id=47: number=46
2020/10/29 01:39:30 trial id=48: number=47
2020/10/29 01:39:30 trial id=49: number=48
2020/10/29 01:39:30 trial id=50: number=49
2020/10/29 01:39:30 trial id=51: number=50
2020/10/29 01:39:30 trial id=52: number=51
2020/10/29 01:39:30 trial id=53: number=52
2020/10/29 01:39:30 trial id=54: number=53
2020/10/29 01:39:30 trial id=55: number=54
2020/10/29 01:39:30 trial id=56: number=55
2020/10/29 01:39:30 trial id=57: number=56
2020/10/29 01:39:30 trial id=58: number=57
2020/10/29 01:39:30 trial id=59: number=58
2020/10/29 01:39:30 trial id=60: number=59
2020/10/29 01:39:30 trial id=61: number=60
2020/10/29 01:39:30 trial id=62: number=61
2020/10/29 01:39:30 trial id=63: number=62
2020/10/29 01:39:30 trial id=64: number=63
2020/10/29 01:39:30 trial id=65: number=64
2020/10/29 01:39:30 trial id=66: number=65
2020/10/29 01:39:30 trial id=67: number=66
2020/10/29 01:39:30 trial id=68: number=67
2020/10/29 01:39:30 trial id=69: number=68
2020/10/29 01:39:30 trial id=70: number=69
2020/10/29 01:39:30 trial id=71: number=70
2020/10/29 01:39:30 trial id=72: number=71
2020/10/29 01:39:30 trial id=73: number=72
2020/10/29 01:39:30 trial id=74: number=73
2020/10/29 01:39:30 trial id=75: number=74
2020/10/29 01:39:30 trial id=76: number=75
2020/10/29 01:39:30 trial id=77: number=75
2020/10/29 01:39:30 trial id=78: number=77
2020/10/29 01:39:30 trial id=79: number=78
2020/10/29 01:39:30 trial id=80: number=79
2020/10/29 01:39:30 trial id=81: number=80
2020/10/29 01:39:30 trial id=82: number=81
2020/10/29 01:39:30 trial id=83: number=82
2020/10/29 01:39:30 trial id=84: number=83
2020/10/29 01:39:30 trial id=85: number=84
2020/10/29 01:39:30 trial id=86: number=85
2020/10/29 01:39:30 trial id=87: number=86
2020/10/29 01:39:30 trial id=88: number=87
2020/10/29 01:39:30 trial id=89: number=88
2020/10/29 01:39:30 trial id=90: number=89
2020/10/29 01:39:30 trial id=91: number=90
2020/10/29 01:39:30 trial id=92: number=91
2020/10/29 01:39:30 trial id=93: number=92
2020/10/29 01:39:30 trial id=94: number=93
2020/10/29 01:39:30 trial id=95: number=94
2020/10/29 01:39:30 trial id=96: number=95
2020/10/29 01:39:30 trial id=97: number=96
2020/10/29 01:39:30 trial id=98: number=97
2020/10/29 01:39:30 trial id=99: number=98
2020/10/29 01:39:30 trial id=100: number=99
2020/10/29 01:39:30 trial id=101: number=100
2020/10/29 01:39:30 trial id=102: number=101
2020/10/29 01:39:30 trial id=103: number=102
2020/10/29 01:39:30 trial id=104: number=103
2020/10/29 01:39:30 trial id=105: number=104
2020/10/29 01:39:30 trial id=106: number=105
2020/10/29 01:39:30 trial id=107: number=106
2020/10/29 01:39:30 trial id=108: number=107
2020/10/29 01:39:30 trial id=109: number=108
2020/10/29 01:39:30 trial id=110: number=109
2020/10/29 01:39:30 trial id=111: number=110
2020/10/29 01:39:30 trial id=112: number=111
2020/10/29 01:39:30 trial id=113: number=112
2020/10/29 01:39:30 trial id=114: number=113
2020/10/29 01:39:30 trial id=115: number=114
2020/10/29 01:39:30 trial id=116: number=115
2020/10/29 01:39:30 trial id=117: number=116
2020/10/29 01:39:30 trial id=118: number=117
2020/10/29 01:39:30 trial id=119: number=118
2020/10/29 01:39:30 trial id=120: number=119
2020/10/29 01:39:30 trial id=121: number=120
2020/10/29 01:39:30 trial id=122: number=121
2020/10/29 01:39:30 trial id=123: number=122
2020/10/29 01:39:30 trial id=124: number=123
2020/10/29 01:39:30 trial id=125: number=124
2020/10/29 01:39:30 trial id=126: number=125
2020/10/29 01:39:30 trial id=127: number=126
2020/10/29 01:39:30 trial id=128: number=127
2020/10/29 01:39:30 trial id=129: number=128
2020/10/29 01:39:30 trial id=130: number=129
2020/10/29 01:39:30 trial id=131: number=130
2020/10/29 01:39:30 trial id=132: number=131
2020/10/29 01:39:30 trial id=133: number=132
2020/10/29 01:39:30 trial id=134: number=133
2020/10/29 01:39:30 trial id=135: number=134
2020/10/29 01:39:30 trial id=136: number=135
2020/10/29 01:39:30 trial id=137: number=136
2020/10/29 01:39:30 trial id=138: number=137
2020/10/29 01:39:30 trial id=139: number=138
2020/10/29 01:39:30 trial id=140: number=139
2020/10/29 01:39:30 trial id=141: number=140
2020/10/29 01:39:30 trial id=142: number=141
2020/10/29 01:39:30 trial id=143: number=142
2020/10/29 01:39:30 trial id=144: number=143
2020/10/29 01:39:30 trial id=145: number=144
2020/10/29 01:39:30 trial id=146: number=145
2020/10/29 01:39:30 trial id=147: number=146
2020/10/29 01:39:30 trial id=148: number=147
2020/10/29 01:39:30 trial id=149: number=148
2020/10/29 01:39:30 trial id=150: number=149
2020/10/29 01:39:30 trial id=151: number=150
2020/10/29 01:39:30 trial id=152: number=151
2020/10/29 01:39:30 trial id=153: number=152
2020/10/29 01:39:30 trial id=154: number=153
2020/10/29 01:39:30 trial id=155: number=153
2020/10/29 01:39:30 trial id=156: number=155
2020/10/29 01:39:30 trial id=157: number=156
2020/10/29 01:39:30 trial id=158: number=157
2020/10/29 01:39:30 trial id=159: number=158
2020/10/29 01:39:30 trial id=160: number=159
2020/10/29 01:39:30 trial id=161: number=160
2020/10/29 01:39:30 trial id=162: number=161
2020/10/29 01:39:30 trial id=163: number=162
2020/10/29 01:39:30 trial id=164: number=163
2020/10/29 01:39:30 trial id=165: number=164
2020/10/29 01:39:30 trial id=166: number=165
2020/10/29 01:39:30 trial id=167: number=166
2020/10/29 01:39:30 trial id=168: number=167
2020/10/29 01:39:30 trial id=169: number=168
2020/10/29 01:39:30 trial id=170: number=169
2020/10/29 01:39:30 trial id=171: number=170
2020/10/29 01:39:30 trial id=172: number=171
2020/10/29 01:39:30 trial id=173: number=172
2020/10/29 01:39:30 trial id=174: number=173
2020/10/29 01:39:30 trial id=175: number=174
2020/10/29 01:39:30 trial id=176: number=175
2020/10/29 01:39:30 trial id=177: number=176
2020/10/29 01:39:30 trial id=178: number=177
2020/10/29 01:39:30 trial id=179: number=178
2020/10/29 01:39:30 trial id=180: number=179
2020/10/29 01:39:30 trial id=181: number=180
2020/10/29 01:39:30 trial id=182: number=181
2020/10/29 01:39:30 trial id=183: number=182
2020/10/29 01:39:30 trial id=184: number=183
2020/10/29 01:39:30 trial id=185: number=184
2020/10/29 01:39:30 trial id=186: number=185
2020/10/29 01:39:30 trial id=187: number=186
2020/10/29 01:39:30 trial id=188: number=187
2020/10/29 01:39:30 trial id=189: number=188
2020/10/29 01:39:30 trial id=190: number=189
2020/10/29 01:39:30 trial id=191: number=190
2020/10/29 01:39:30 trial id=192: number=191
2020/10/29 01:39:30 trial id=193: number=192
2020/10/29 01:39:30 trial id=194: number=193
2020/10/29 01:39:30 trial id=195: number=194
2020/10/29 01:39:30 trial id=196: number=195
2020/10/29 01:39:30 trial id=197: number=196
2020/10/29 01:39:30 trial id=198: number=197
2020/10/29 01:39:30 trial id=199: number=198
2020/10/29 01:39:30 trial id=200: number=199

After #168

package main

import (
	"context"
	"flag"
	"log"
	"math"

	"github.com/c-bata/goptuna"
	"github.com/c-bata/goptuna/rdb.v2"
	"github.com/c-bata/goptuna/tpe"
	"golang.org/x/sync/errgroup"
	"gorm.io/driver/mysql"
	"gorm.io/driver/sqlite"
	"gorm.io/gorm"
)

func objective(trial goptuna.Trial) (float64, error) {
	x1, _ := trial.SuggestFloat("x1", -10, 10)
	x2, _ := trial.SuggestFloat("x2", -10, 10)
	return math.Pow(x1-2, 2) + math.Pow(x2+5, 2), nil
}

func main() {
	flag.Parse()
	if len(flag.Args()) == 0 {
		log.Fatal("please pass dialect and dsn")
	}
	dialect := flag.Arg(0)
	dsn := flag.Arg(1)

	var db *gorm.DB
	var err error
	if dialect == "sqlite3" {
		db, err = gorm.Open(sqlite.Open(dsn), &gorm.Config{})
	} else if dialect == "mysql" {
		db, err = gorm.Open(mysql.Open(dsn), &gorm.Config{})
	} else {
		log.Fatal("unsupported dialect")
	}
	if err != nil {
		log.Fatal("failed to open db:", err)
	}
	err = rdb.RunAutoMigrate(db)
	if err != nil {
		log.Fatal("failed to run auto migrate:", err)
	}

	study, err := goptuna.CreateStudy(
		"rdb",
		goptuna.StudyOptionStorage(rdb.NewStorage(db)),
		goptuna.StudyOptionSampler(tpe.NewSampler()),
		goptuna.StudyOptionDirection(goptuna.StudyDirectionMinimize),
		goptuna.StudyOptionLoadIfExists(true),
	)
	if err != nil {
		log.Fatal("failed to create study", err)
	}

	eg, ctx := errgroup.WithContext(context.Background())
	study.WithContext(ctx)
	for i := 0; i < 10; i++ {
		eg.Go(func() error {
			return study.Optimize(objective, 20)
		})
	}
	if err := eg.Wait(); err != nil {
		log.Fatal("Optimize error", err)
	}

	trials, err := study.GetTrials()
	if err != nil {
		log.Fatal("failed to get trials", err)
	}
	for i := range trials {
		log.Printf("trial id=%d: number=%d\n", trials[i].ID, trials[i].Number)
	}

	v, err := study.GetBestValue()
	if err != nil {
		log.Fatal("failed to get best value", err)
	}
	params, err := study.GetBestParams()
	if err != nil {
		log.Fatal("failed to get best params:", err)
	}
	log.Printf("Best evaluation=%f (x1=%f, x2=%f)",
		v, params["x1"].(float64), params["x2"].(float64))
}

2020/10/29 02:16:13 trial id=1: number=0
2020/10/29 02:16:13 trial id=2: number=1
2020/10/29 02:16:13 trial id=3: number=2
2020/10/29 02:16:13 trial id=4: number=3
2020/10/29 02:16:13 trial id=5: number=4
2020/10/29 02:16:13 trial id=6: number=5
2020/10/29 02:16:13 trial id=7: number=6
2020/10/29 02:16:13 trial id=8: number=7
2020/10/29 02:16:13 trial id=9: number=8
2020/10/29 02:16:13 trial id=10: number=9
2020/10/29 02:16:13 trial id=11: number=10
2020/10/29 02:16:13 trial id=12: number=11
2020/10/29 02:16:13 trial id=13: number=12
2020/10/29 02:16:13 trial id=14: number=13
2020/10/29 02:16:13 trial id=15: number=14
2020/10/29 02:16:13 trial id=16: number=15
2020/10/29 02:16:13 trial id=17: number=16
2020/10/29 02:16:13 trial id=18: number=17
2020/10/29 02:16:13 trial id=19: number=18
2020/10/29 02:16:13 trial id=20: number=19
2020/10/29 02:16:13 trial id=21: number=20
2020/10/29 02:16:13 trial id=22: number=21
2020/10/29 02:16:13 trial id=23: number=22
2020/10/29 02:16:13 trial id=24: number=23
2020/10/29 02:16:13 trial id=25: number=24
2020/10/29 02:16:13 trial id=26: number=25
2020/10/29 02:16:13 trial id=27: number=26
2020/10/29 02:16:13 trial id=28: number=27
2020/10/29 02:16:13 trial id=29: number=28
2020/10/29 02:16:13 trial id=30: number=29
2020/10/29 02:16:13 trial id=31: number=30
2020/10/29 02:16:13 trial id=32: number=31
2020/10/29 02:16:13 trial id=33: number=32
2020/10/29 02:16:13 trial id=34: number=33
2020/10/29 02:16:13 trial id=35: number=34
2020/10/29 02:16:13 trial id=36: number=35
2020/10/29 02:16:13 trial id=37: number=36
2020/10/29 02:16:13 trial id=38: number=37
2020/10/29 02:16:13 trial id=39: number=38
2020/10/29 02:16:13 trial id=40: number=39
2020/10/29 02:16:13 trial id=41: number=40
2020/10/29 02:16:13 trial id=42: number=41
2020/10/29 02:16:13 trial id=43: number=42
2020/10/29 02:16:13 trial id=44: number=43
2020/10/29 02:16:13 trial id=45: number=44
2020/10/29 02:16:13 trial id=46: number=45
2020/10/29 02:16:13 trial id=47: number=46
2020/10/29 02:16:13 trial id=48: number=47
2020/10/29 02:16:13 trial id=49: number=48
2020/10/29 02:16:13 trial id=50: number=49
2020/10/29 02:16:13 trial id=51: number=50
2020/10/29 02:16:13 trial id=52: number=51
2020/10/29 02:16:13 trial id=53: number=52
2020/10/29 02:16:13 trial id=54: number=53
2020/10/29 02:16:13 trial id=55: number=54
2020/10/29 02:16:13 trial id=56: number=55
2020/10/29 02:16:13 trial id=57: number=56
2020/10/29 02:16:13 trial id=58: number=57
2020/10/29 02:16:13 trial id=59: number=58
2020/10/29 02:16:13 trial id=60: number=59
2020/10/29 02:16:13 trial id=61: number=60
2020/10/29 02:16:13 trial id=62: number=61
2020/10/29 02:16:13 trial id=63: number=62
2020/10/29 02:16:13 trial id=64: number=63
2020/10/29 02:16:13 trial id=65: number=64
2020/10/29 02:16:13 trial id=66: number=65
2020/10/29 02:16:13 trial id=67: number=66
2020/10/29 02:16:13 trial id=68: number=67
2020/10/29 02:16:13 trial id=69: number=68
2020/10/29 02:16:13 trial id=70: number=69
2020/10/29 02:16:13 trial id=71: number=70
2020/10/29 02:16:13 trial id=72: number=71
2020/10/29 02:16:13 trial id=73: number=72
2020/10/29 02:16:13 trial id=74: number=73
2020/10/29 02:16:13 trial id=75: number=74
2020/10/29 02:16:13 trial id=76: number=75
2020/10/29 02:16:13 trial id=77: number=76
2020/10/29 02:16:13 trial id=78: number=77
2020/10/29 02:16:13 trial id=79: number=78
2020/10/29 02:16:13 trial id=80: number=79
2020/10/29 02:16:13 trial id=81: number=80
2020/10/29 02:16:13 trial id=82: number=81
2020/10/29 02:16:13 trial id=83: number=82
2020/10/29 02:16:13 trial id=84: number=83
2020/10/29 02:16:13 trial id=85: number=84
2020/10/29 02:16:13 trial id=86: number=85
2020/10/29 02:16:13 trial id=87: number=86
2020/10/29 02:16:13 trial id=88: number=87
2020/10/29 02:16:13 trial id=89: number=88
2020/10/29 02:16:13 trial id=90: number=89
2020/10/29 02:16:13 trial id=91: number=90
2020/10/29 02:16:13 trial id=92: number=91
2020/10/29 02:16:13 trial id=93: number=92
2020/10/29 02:16:13 trial id=94: number=93
2020/10/29 02:16:13 trial id=95: number=94
2020/10/29 02:16:13 trial id=96: number=95
2020/10/29 02:16:13 trial id=97: number=96
2020/10/29 02:16:13 trial id=98: number=97
2020/10/29 02:16:13 trial id=99: number=98
2020/10/29 02:16:13 trial id=100: number=99
2020/10/29 02:16:13 Best evaluation=0.130782 (x1=1.718881, x2=-5.227495)