Make cmd.String() faster

command.go

@@ -5,7 +5,6 @@ import (
 	"fmt"
 	"net"
 	"strconv"
-	"strings"
 	"time"
 
 	"github.com/go-redis/redis/v8/internal"
@@ -56,26 +55,6 @@ func writeCmd(wr *proto.Writer, cmd Cmder) error {
 	return wr.WriteArgs(cmd.Args())
 }
 
-func cmdString(cmd Cmder, val interface{}) string {
-	ss := make([]string, 0, len(cmd.Args()))
-	for _, arg := range cmd.Args() {
-		ss = append(ss, fmt.Sprint(arg))
-	}
-	s := strings.Join(ss, " ")
-	if err := cmd.Err(); err != nil {
-		return s + ": " + err.Error()
-	}
-	if val != nil {
-		switch vv := val.(type) {
-		case []byte:
-			return s + ": " + string(vv)
-		default:
-			return s + ": " + fmt.Sprint(val)
-		}
-	}
-	return s
-}
-
 func cmdFirstKeyPos(cmd Cmder, info *CommandInfo) int {
 	switch cmd.Name() {
 	case "eval", "evalsha":
@@ -93,6 +72,65 @@ func cmdFirstKeyPos(cmd Cmder, info *CommandInfo) int {
 	return int(info.FirstKeyPos)
 }
 
+func cmdString(cmd Cmder, val interface{}) string {
+	b := make([]byte, 0, 32)
+
+	for i, arg := range cmd.Args() {
+		if i > 0 {
+			b = append(b, ' ')
+		}
+		b = appendArg(b, arg)
+	}
+
+	if err := cmd.Err(); err != nil {
+		b = append(b, ": "...)
+		b = append(b, err.Error()...)
+	} else if val != nil {
+		b = append(b, ": "...)
+
+		switch val := val.(type) {
+		case []byte:
+			b = append(b, val...)
+		default:
+			b = appendArg(b, val)
+		}
+	}
+
+	return string(b)
+}
+
+func appendArg(b []byte, v interface{}) []byte {
+	switch v := v.(type) {
+	case nil:
+		return append(b, "<nil>"...)
+	case string:
+		return append(b, v...)
+	case []byte:
+		return append(b, v...)
+	case int:
+		return strconv.AppendInt(b, int64(v), 10)
+	case int32:
+		return strconv.AppendInt(b, int64(v), 10)
+	case int64:
+		return strconv.AppendInt(b, v, 10)
+	case uint:
+		return strconv.AppendUint(b, uint64(v), 10)
+	case uint32:
+		return strconv.AppendUint(b, uint64(v), 10)
+	case uint64:
+		return strconv.AppendUint(b, v, 10)
+	case bool:
+		if v {
+			return append(b, "true"...)
+		}
+		return append(b, "false"...)
+	case time.Time:
+		return v.AppendFormat(b, time.RFC3339Nano)
+	default:
+		return append(b, fmt.Sprint(v)...)
+	}
+}
+
 //------------------------------------------------------------------------------
 
 type baseCmd struct {

internal/proto/writer.go

@@ -93,7 +93,8 @@ func (w *Writer) writeArg(v interface{}) error {
 		}
 		return w.int(0)
 	case time.Time:
-		return w.string(v.Format(time.RFC3339))
+		w.numBuf = v.AppendFormat(w.numBuf[:0], time.RFC3339Nano)
+		return w.bytes(w.numBuf)
 	case encoding.BinaryMarshaler:
 		b, err := v.MarshalBinary()
 		if err != nil {