diff --git a/ChangeLog b/ChangeLog
index 82e13b6..ca1fd63 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2019-08-09 Alibaba Cloud.
+	* VERSION: 1.6.15
+	* IMPROVE: add `target.version` to support some proxy like twemproxy.
+	* BUGFIX: filter `select` command in `rump` when only db0 supports in some
+	redis version.
+	* IMPROVE: remove the cluster limit when target type is rump.
+	* IMPROVE: add `scan.key_number` limit judge when target type is cluster
+	in type `rump`. see #136.
 2019-08-01 Alibaba Cloud.
 	* VERSION: 1.6.14
 	* BUGFIX: the `rdb.parallel` parameter limits concurrency without effect.
diff --git a/README.md b/README.md
index 15dfb22..4292327 100644
--- a/README.md
+++ b/README.md
@@ -26,7 +26,8 @@ Please check out the `conf/redis-shake.conf` to see the detailed parameters desc
 # Support
 ---
 Redis version from 2.x to 5.0.
-Supports `Standalone`, `Cluster`, `Codis`, `Aliyun Cluster Proxy`, `Tencent Cloud Proxy` and so on.
+Supports `Standalone`, `Cluster`, and some proxies type like `Codis`, `twemproxy`,  `Aliyun Cluster Proxy`, `Tencent Cloud Proxy` and so on.<br>
+For `codis` and `twemproxy`, there maybe some constraints, please checkout this [question](https://github.com/alibaba/RedisShake/wiki/FAQ#q-does-redisshake-supports-codis-and-twemproxy).
 
 # Configuration
 Redis-shake has several parameters in the configuration(`conf/redis-shake.conf`) that maybe confusing, if this is your first time using, just configure the `source.address` and `target.address` parameters.
diff --git a/conf/redis-shake.conf b/conf/redis-shake.conf
index bdaa0ac..08b30dc 100644
--- a/conf/redis-shake.conf
+++ b/conf/redis-shake.conf
@@ -98,6 +98,9 @@ target.tls_enable = false
 # 如果是decode或者dump，这个参数表示输出的rdb前缀，比如输入有3个db，那么dump分别是:
 # ${output_rdb}.0, ${output_rdb}.1, ${output_rdb}.2
 target.rdb.output = local_dump
+# some redis proxy like twemproxy doesn't support to fetch version, so please set it here.
+# e.g., target.version = 4.0
+target.version =
 
 # use for expire key, set the time gap when source and target timestamp are not the same.
 # 用于处理过期的键值，当迁移两端不一致的时候，目的端需要加上这个值
diff --git a/src/redis-shake/common/configure.go b/src/redis-shake/common/configure.go
index 5a0b597..bbf6cfe 100644
--- a/src/redis-shake/common/configure.go
+++ b/src/redis-shake/common/configure.go
@@ -96,9 +96,9 @@ func parseAddress(tp, address, redisType string, isSource bool) error {
 			}
 		}
 	case conf.RedisTypeCluster:
-		if isSource == false && tp == conf.TypeRump {
-			return fmt.Errorf("target type[%v] can't be cluster when type is 'rump' currently", redisType)
-		}
+		//if isSource == false && tp == conf.TypeRump {
+		//	return fmt.Errorf("target type[%v] can't be cluster when type is 'rump' currently", redisType)
+		//}
 		if strings.Contains(address, AddressSplitter) {
 			arr := strings.Split(address, AddressSplitter)
 			if len(arr) != 2 {
diff --git a/src/redis-shake/common/split.go b/src/redis-shake/common/split.go
index bbf53b2..10ffdd6 100644
--- a/src/redis-shake/common/split.go
+++ b/src/redis-shake/common/split.go
@@ -8,9 +8,12 @@ import (
 	redigo "github.com/garyburd/redigo/redis"
 )
 
-func RestoreBigkey(client redigo.Conn, key string, value string, pttl int64, db int) {
-	if _, err := client.Do("select", db); err != nil {
-		log.Panicf("send select db[%v] failed[%v]", db, err)
+func RestoreBigkey(client redigo.Conn, key string, value string, pttl int64, db int, preDb *int) {
+	if db != *preDb {
+		if _, err := client.Do("select", db); err != nil {
+			log.Panicf("send select db[%v] failed[%v]", db, err)
+		}
+		*preDb = db
 	}
 
 	entry := rdb.BinEntry{
diff --git a/src/redis-shake/configure/configure.go b/src/redis-shake/configure/configure.go
index 2c9e15a..5a8cc85 100644
--- a/src/redis-shake/configure/configure.go
+++ b/src/redis-shake/configure/configure.go
@@ -15,7 +15,6 @@ type Configuration struct {
 	SourceAddress             string   `config:"source.address"`
 	SourcePasswordRaw         string   `config:"source.password_raw"`
 	SourcePasswordEncoding    string   `config:"source.password_encoding"`
-	SourceVersion             uint     `config:"source.version"`
 	SourceAuthType            string   `config:"source.auth_type"`
 	SourceTLSEnable           bool     `config:"source.tls_enable"`
 	SourceRdbInput            []string `config:"source.rdb.input"`
@@ -24,12 +23,12 @@ type Configuration struct {
 	TargetAddress             string   `config:"target.address"`
 	TargetPasswordRaw         string   `config:"target.password_raw"`
 	TargetPasswordEncoding    string   `config:"target.password_encoding"`
-	TargetVersion             uint     `config:"target.version"`
 	TargetDBString            string   `config:"target.db"`
 	TargetAuthType            string   `config:"target.auth_type"`
 	TargetType                string   `config:"target.type"`
 	TargetTLSEnable           bool     `config:"target.tls_enable"`
 	TargetRdbOutput           string   `config:"target.rdb.output"`
+	TargetVersion             string   `config:"target.version"`
 	FakeTime                  string   `config:"fake_time"`
 	Rewrite                   bool     `config:"rewrite"`
 	FilterDBWhitelist         []string `config:"filter.db.whitelist"`
@@ -67,15 +66,14 @@ type Configuration struct {
 
 	/*---------------------------------------------------------*/
 	// generated variables
-	SourceAddressList  []string      // source address list
-	TargetAddressList  []string      // target address list
-	HeartbeatIp        string        // heartbeat ip
-	ShiftTime          time.Duration // shift
-	TargetRedisVersion string        // to_redis_version
-	TargetReplace      bool          // to_replace
-	TargetDB           int           // int type
-	Version            string        // version
-	Type               string        // input mode -type=xxx
+	SourceAddressList []string      // source address list
+	TargetAddressList []string      // target address list
+	HeartbeatIp       string        // heartbeat ip
+	ShiftTime         time.Duration // shift
+	TargetReplace     bool          // to_replace
+	TargetDB          int           // int type
+	Version           string        // version
+	Type              string        // input mode -type=xxx
 }
 
 var Options Configuration
diff --git a/src/redis-shake/main/main.go b/src/redis-shake/main/main.go
index 89fcb72..3ee087c 100644
--- a/src/redis-shake/main/main.go
+++ b/src/redis-shake/main/main.go
@@ -409,21 +409,24 @@ func sanitizeOptions(tp string) error {
 	}
 
 	if tp == conf.TypeRestore || tp == conf.TypeSync || tp == conf.TypeRump {
-		// get target redis version and set TargetReplace.
-		for _, address := range conf.Options.TargetAddressList {
-			// single connection even if the target is cluster
-			if v, err := utils.GetRedisVersion(address, conf.Options.TargetAuthType,
-				conf.Options.TargetPasswordRaw, conf.Options.TargetTLSEnable); err != nil {
-				return fmt.Errorf("get target redis version failed[%v]", err)
-			} else if conf.Options.TargetRedisVersion != "" && conf.Options.TargetRedisVersion != v {
-				return fmt.Errorf("target redis version is different: [%v %v]", conf.Options.TargetRedisVersion, v)
-			} else {
-				conf.Options.TargetRedisVersion = v
+		if conf.Options.TargetVersion == "" {
+			// get target redis version and set TargetReplace.
+			for _, address := range conf.Options.TargetAddressList {
+				// single connection even if the target is cluster
+				if v, err := utils.GetRedisVersion(address, conf.Options.TargetAuthType,
+					conf.Options.TargetPasswordRaw, conf.Options.TargetTLSEnable); err != nil {
+					return fmt.Errorf("get target redis version failed[%v]", err)
+				} else if conf.Options.TargetVersion != "" && conf.Options.TargetVersion != v {
+					return fmt.Errorf("target redis version is different: [%v %v]", conf.Options.TargetVersion, v)
+				} else {
+					conf.Options.TargetVersion = v
+				}
 			}
 		}
-		if strings.HasPrefix(conf.Options.TargetRedisVersion, "4.") ||
-			strings.HasPrefix(conf.Options.TargetRedisVersion, "3.") ||
-			strings.HasPrefix(conf.Options.TargetRedisVersion, "5.") {
+
+		if strings.HasPrefix(conf.Options.TargetVersion, "4.") ||
+			strings.HasPrefix(conf.Options.TargetVersion, "3.") ||
+			strings.HasPrefix(conf.Options.TargetVersion, "5.") {
 			conf.Options.TargetReplace = true
 		} else {
 			conf.Options.TargetReplace = false
@@ -445,6 +448,10 @@ func sanitizeOptions(tp string) error {
 				conf.Options.ScanSpecialCloud, conf.Options.ScanKeyFile)
 		}
 
+		if conf.Options.ScanKeyNumber > utils.RecvChanSize && conf.Options.TargetType == conf.RedisTypeCluster {
+			return fmt.Errorf("scan.key_number should less than [%v] when target type is cluster", utils.RecvChanSize)
+		}
+
 		//if len(conf.Options.SourceAddressList) == 1 {
 		//	return fmt.Errorf("source address length should == 1 when type is 'rump'")
 		//}
diff --git a/src/redis-shake/rump.go b/src/redis-shake/rump.go
index 87feac8..aaf1b25 100644
--- a/src/redis-shake/rump.go
+++ b/src/redis-shake/rump.go
@@ -327,6 +327,7 @@ func (dre *dbRumperExecutor) writer() {
 	// used in QoS
 	bucket := utils.StartQoS(conf.Options.Qps)
 	preDb := 0
+	preBigKeyDb := 0
 	for ele := range dre.keyChan {
 		if filter.FilterKey(ele.key) {
 			continue
@@ -354,8 +355,7 @@ func (dre *dbRumperExecutor) writer() {
 			batch = dre.writeSend(batch, &count, &wBytes)
 
 			// handle big key
-			utils.RestoreBigkey(dre.targetBigKeyClient, ele.key, ele.value, ele.pttl, ele.db)
-
+			utils.RestoreBigkey(dre.targetBigKeyClient, ele.key, ele.value, ele.pttl, ele.db, &preBigKeyDb)
 			// all the reply has been handled in RestoreBigkey
 			// dre.resultChan <- ele
 			continue