fix(utils): speedup random string generation

pkg/coltypes/simple_type.go

@@ -158,10 +158,10 @@ func (st SimpleType) GenValue(r *rand.Rand, p *typedef.PartitionRangeConfig) []i
 	switch st {
 	case TYPE_ASCII, TYPE_TEXT, TYPE_VARCHAR:
 		ln := r.Intn(p.MaxStringLength) + p.MinStringLength
-		val = utils.RandStringWithTime(r, ln, utils.RandTime(r))
+		val = utils.RandString(r, ln)
 	case TYPE_BLOB:
 		ln := r.Intn(p.MaxBlobLength) + p.MinBlobLength
-		val = hex.EncodeToString([]byte(utils.RandStringWithTime(r, ln, utils.RandTime(r))))
+		val = hex.EncodeToString([]byte(utils.RandString(r, ln)))
 	case TYPE_BIGINT:
 		val = r.Int63()
 	case TYPE_BOOLEAN:

pkg/utils/utils.go

@@ -15,33 +15,15 @@
 package utils
 
 import (
-	"encoding/base64"
+	"encoding/hex"
 	"fmt"
 	"strconv"
 	"strings"
 	"time"
 
-	"github.com/segmentio/ksuid"
 	"golang.org/x/exp/rand"
 )
 
-func RandStringWithTime(rnd *rand.Rand, len int, t time.Time) string {
-	id, _ := ksuid.NewRandomWithTime(t)
-
-	var buf strings.Builder
-	buf.WriteString(id.String())
-	if buf.Len() >= len {
-		return buf.String()[:len]
-	}
-
-	// Pad some extra random data
-	buff := make([]byte, len-buf.Len())
-	_, _ = rnd.Read(buff)
-	buf.WriteString(base64.StdEncoding.EncodeToString(buff))
-
-	return buf.String()[:len]
-}
-
 func RandDate(rnd *rand.Rand) string {
 	return RandTime(rnd).Format("2006-01-02")
 }
@@ -51,7 +33,7 @@ func RandTime(rnd *rand.Rand) time.Time {
 	max := time.Date(2024, 1, 0, 0, 0, 0, 0, time.UTC).Unix()
 
 	sec := rnd.Int63n(max-min) + min
-	return time.Unix(sec, 0)
+	return time.Unix(sec, 0).UTC()
 }
 
 func RandIpV4Address(rnd *rand.Rand, v, pos int) string {
@@ -82,3 +64,21 @@ func RandInt(min, max int) int {
 func IgnoreError(fn func() error) {
 	_ = fn()
 }
+
+func RandString(rnd *rand.Rand, ln int) string {
+	buffLen := ln
+	if buffLen > 32 {
+		buffLen = 32
+	}
+	binBuff := make([]byte, buffLen/2+1)
+	_, _ = rnd.Read(binBuff)
+	buff := hex.EncodeToString(binBuff)[:buffLen]
+	if ln <= 32 {
+		return buff
+	}
+	out := make([]byte, ln+buffLen)
+	for idx := 0; idx < ln+buffLen; idx += buffLen {
+		copy(out[idx:], buff)
+	}
+	return string(out[:ln])
+}

pkg/utils/utils_slow_test.go → pkg/utils/utils_test.go

@@ -12,33 +12,37 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//go:build slow
-// +build slow
-
 package utils_test
 
 import (
-	"github.com/scylladb/gemini/pkg/utils"
-	"golang.org/x/exp/rand"
 	"testing"
-	"testing/quick"
 	"time"
+
+	"golang.org/x/exp/rand"
+
+	"github.com/scylladb/gemini/pkg/utils"
 )
 
 var rnd = rand.New(rand.NewSource(uint64(time.Now().UnixNano())))
 
-func TestNonEmptyRandString(t *testing.T) {
-	// TODO: Figure out why this is so horribly slow...
-	tt := time.Now()
-	f := func(len int32) bool {
-		if len < 0 {
-			len = -len
-		}
-		r := utils.RandStringWithTime(rnd, int(len), tt)
-		return r != ""
+func BenchmarkUtilsRandString100(t *testing.B) {
+	for x := 0; x < t.N; x++ {
+		utils.RandString(rnd, 100)
+	}
+}
+
+func BenchmarkUtilsRandString1000(t *testing.B) {
+	for x := 0; x < t.N; x++ {
+		utils.RandString(rnd, 1000)
 	}
-	cfg := &quick.Config{MaxCount: 10}
-	if err := quick.Check(f, cfg); err != nil {
-		t.Error(err)
+}
+
+func TestRandString(t *testing.T) {
+	for _, ln := range []int{1, 3, 5, 16, 45, 100, 1000} {
+		out := utils.RandString(rnd, ln)
+		if len(out) != ln {
+			t.Fatalf("%d != %d", ln, len(out))
+		}
+		println(out)
 	}
 }