diff --git a/pkg/proxy/backend/backend_conn_mgr.go b/pkg/proxy/backend/backend_conn_mgr.go
index 6cc15549..9aa00cb1 100644
--- a/pkg/proxy/backend/backend_conn_mgr.go
+++ b/pkg/proxy/backend/backend_conn_mgr.go
@@ -260,7 +260,7 @@ func (mgr *BackendConnManager) ExecuteCmd(ctx context.Context, request []byte) (
 		err = mysql.ErrMalformPacket
 		return
 	}
-	cmd := request[0]
+	cmd := pnet.Command(request[0])
 	startTime := time.Now()
 	mgr.processLock.Lock()
 	defer mgr.processLock.Unlock()
@@ -285,9 +285,9 @@ func (mgr *BackendConnManager) ExecuteCmd(ctx context.Context, request []byte) (
 	}
 	if err == nil {
 		switch cmd {
-		case mysql.ComQuit:
+		case pnet.ComQuit:
 			return
-		case mysql.ComSetOption:
+		case pnet.ComSetOption:
 			val := binary.LittleEndian.Uint16(request[1:])
 			switch val {
 			case 0:
@@ -300,7 +300,7 @@ func (mgr *BackendConnManager) ExecuteCmd(ctx context.Context, request []byte) (
 				err = errors.Errorf("unrecognized set_option value:%d", val)
 				return
 			}
-		case mysql.ComChangeUser:
+		case pnet.ComChangeUser:
 			username, db := pnet.ParseChangeUser(request)
 			mgr.authenticator.changeUser(username, db)
 			return
diff --git a/pkg/proxy/backend/backend_conn_mgr_test.go b/pkg/proxy/backend/backend_conn_mgr_test.go
index 1c6a8a9a..e9885c5d 100644
--- a/pkg/proxy/backend/backend_conn_mgr_test.go
+++ b/pkg/proxy/backend/backend_conn_mgr_test.go
@@ -148,10 +148,10 @@ func (ts *backendMgrTester) forwardCmd4Proxy(clientIO, backendIO *pnet.PacketIO)
 	clientIO.ResetSequence()
 	request, err := clientIO.ReadPacket()
 	require.NoError(ts.t, err)
-	prevCounter, err := readCmdCounter(request[0], ts.tc.backendListener.Addr().String())
+	prevCounter, err := readCmdCounter(pnet.Command(request[0]), ts.tc.backendListener.Addr().String())
 	require.NoError(ts.t, err)
 	rsErr := ts.mp.ExecuteCmd(context.Background(), request)
-	curCounter, err := readCmdCounter(request[0], ts.tc.backendListener.Addr().String())
+	curCounter, err := readCmdCounter(pnet.Command(request[0]), ts.tc.backendListener.Addr().String())
 	require.NoError(ts.t, err)
 	require.Equal(ts.t, prevCounter+1, curCounter)
 	return rsErr
@@ -470,7 +470,7 @@ func TestSpecialCmds(t *testing.T) {
 		// change user
 		{
 			client: func(packetIO *pnet.PacketIO) error {
-				ts.mc.cmd = mysql.ComChangeUser
+				ts.mc.cmd = pnet.ComChangeUser
 				ts.mc.username = "another_user"
 				ts.mc.dbName = "another_db"
 				return ts.mc.request(packetIO)
@@ -481,7 +481,7 @@ func TestSpecialCmds(t *testing.T) {
 		// disable multi-stmts
 		{
 			client: func(packetIO *pnet.PacketIO) error {
-				ts.mc.cmd = mysql.ComSetOption
+				ts.mc.cmd = pnet.ComSetOption
 				ts.mc.dataBytes = []byte{1, 0}
 				return ts.mc.request(packetIO)
 			},
diff --git a/pkg/proxy/backend/cmd_processor.go b/pkg/proxy/backend/cmd_processor.go
index 5bd601d0..c224dfa5 100644
--- a/pkg/proxy/backend/cmd_processor.go
+++ b/pkg/proxy/backend/cmd_processor.go
@@ -68,24 +68,24 @@ func (cp *CmdProcessor) updatePrepStmtStatus(request []byte, serverStatus uint16
 		stmtID         int
 		prepStmtStatus uint32
 	)
-	cmd := request[0]
+	cmd := pnet.Command(request[0])
 	switch cmd {
-	case mysql.ComStmtSendLongData, mysql.ComStmtExecute, mysql.ComStmtFetch, mysql.ComStmtReset, mysql.ComStmtClose:
+	case pnet.ComStmtSendLongData, pnet.ComStmtExecute, pnet.ComStmtFetch, pnet.ComStmtReset, pnet.ComStmtClose:
 		stmtID = int(binary.LittleEndian.Uint32(request[1:5]))
-	case mysql.ComResetConnection, mysql.ComChangeUser:
+	case pnet.ComResetConnection, pnet.ComChangeUser:
 		cp.preparedStmtStatus = make(map[int]uint32)
 		return
 	default:
 		return
 	}
 	switch cmd {
-	case mysql.ComStmtSendLongData:
+	case pnet.ComStmtSendLongData:
 		prepStmtStatus = StatusPrepareWaitExecute
-	case mysql.ComStmtExecute:
+	case pnet.ComStmtExecute:
 		if serverStatus&mysql.ServerStatusCursorExists > 0 {
 			prepStmtStatus = StatusPrepareWaitFetch
 		}
-	case mysql.ComStmtFetch:
+	case pnet.ComStmtFetch:
 		if serverStatus&mysql.ServerStatusLastRowSend == 0 {
 			prepStmtStatus = StatusPrepareWaitFetch
 		}
diff --git a/pkg/proxy/backend/cmd_processor_exec.go b/pkg/proxy/backend/cmd_processor_exec.go
index fbb93d26..040fb369 100644
--- a/pkg/proxy/backend/cmd_processor_exec.go
+++ b/pkg/proxy/backend/cmd_processor_exec.go
@@ -37,8 +37,8 @@ func (cp *CmdProcessor) executeCmd(request []byte, clientIO, backendIO *pnet.Pac
 }
 
 func (cp *CmdProcessor) forwardCommand(clientIO, backendIO *pnet.PacketIO, request []byte) error {
-	cmd := request[0]
-	if cmd != mysql.ComChangeUser {
+	cmd := pnet.Command(request[0])
+	if cmd != pnet.ComChangeUser {
 		if err := backendIO.WritePacket(request, true); err != nil {
 			return err
 		}
@@ -49,23 +49,23 @@ func (cp *CmdProcessor) forwardCommand(clientIO, backendIO *pnet.PacketIO, reque
 		}
 	}
 	switch cmd {
-	case mysql.ComStmtPrepare:
+	case pnet.ComStmtPrepare:
 		return cp.forwardPrepareCmd(clientIO, backendIO)
-	case mysql.ComStmtFetch:
+	case pnet.ComStmtFetch:
 		return cp.forwardFetchCmd(clientIO, backendIO, request)
-	case mysql.ComQuery, mysql.ComStmtExecute, mysql.ComProcessInfo:
+	case pnet.ComQuery, pnet.ComStmtExecute, pnet.ComProcessInfo:
 		return cp.forwardQueryCmd(clientIO, backendIO, request)
-	case mysql.ComStmtClose:
+	case pnet.ComStmtClose:
 		return cp.forwardCloseCmd(request)
-	case mysql.ComStmtSendLongData:
+	case pnet.ComStmtSendLongData:
 		return cp.forwardSendLongDataCmd(request)
-	case mysql.ComChangeUser:
+	case pnet.ComChangeUser:
 		return cp.forwardChangeUserCmd(clientIO, backendIO, request)
-	case mysql.ComStatistics:
+	case pnet.ComStatistics:
 		return cp.forwardStatisticsCmd(clientIO, backendIO)
-	case mysql.ComFieldList:
+	case pnet.ComFieldList:
 		return cp.forwardFieldListCmd(clientIO, backendIO, request)
-	case mysql.ComQuit:
+	case pnet.ComQuit:
 		return cp.forwardQuitCmd()
 	}
 
@@ -158,7 +158,7 @@ func (cp *CmdProcessor) forwardPrepareCmd(clientIO, backendIO *pnet.PacketIO) er
 		return cp.handleErrorPacket(response)
 	}
 	// impossible here
-	return errors.Errorf("unexpected response, cmd:%d resp:%d", mysql.ComStmtPrepare, response[0])
+	return errors.Errorf("unexpected response, cmd:%d resp:%d", pnet.ComStmtPrepare, response[0])
 }
 
 func (cp *CmdProcessor) forwardFetchCmd(clientIO, backendIO *pnet.PacketIO, request []byte) error {
@@ -231,7 +231,7 @@ func (cp *CmdProcessor) forwardLoadInFile(clientIO, backendIO *pnet.PacketIO, re
 		return serverStatus, cp.handleErrorPacket(response)
 	}
 	// impossible here
-	return serverStatus, errors.Errorf("unexpected response, cmd:%d resp:%d", mysql.ComQuery, response[0])
+	return serverStatus, errors.Errorf("unexpected response, cmd:%d resp:%d", pnet.ComQuery, response[0])
 }
 
 func (cp *CmdProcessor) forwardResultSet(clientIO, backendIO *pnet.PacketIO, request []byte) (uint16, error) {
@@ -310,9 +310,9 @@ func (cp *CmdProcessor) forwardQuitCmd() error {
 // The application may always omit `COMMIT` and thus the session can never be redirected.
 // We can send a `COMMIT` statement to the current backend and then forward the `BEGIN` statement to the new backend.
 func (cp *CmdProcessor) needHoldRequest(request []byte) bool {
-	cmd, data := request[0], request[1:]
+	cmd, data := pnet.Command(request[0]), request[1:]
 	// BEGIN/START TRANSACTION statements cannot be prepared.
-	if cmd != mysql.ComQuery {
+	if cmd != pnet.ComQuery {
 		return false
 	}
 	// Hold request only when it's waiting for the end of the transaction.
diff --git a/pkg/proxy/backend/cmd_processor_query.go b/pkg/proxy/backend/cmd_processor_query.go
index 79eff310..87792a45 100644
--- a/pkg/proxy/backend/cmd_processor_query.go
+++ b/pkg/proxy/backend/cmd_processor_query.go
@@ -21,7 +21,7 @@ func (cp *CmdProcessor) query(packetIO *pnet.PacketIO, sql string) (result *gomy
 	packetIO.ResetSequence()
 	data := hack.Slice(sql)
 	request := make([]byte, 0, 1+len(data))
-	request = append(request, mysql.ComQuery)
+	request = append(request, pnet.ComQuery.Byte())
 	request = append(request, data...)
 	if err = packetIO.WritePacket(request, true); err != nil {
 		return
diff --git a/pkg/proxy/backend/cmd_processor_test.go b/pkg/proxy/backend/cmd_processor_test.go
index 710c71e9..f2adeb62 100644
--- a/pkg/proxy/backend/cmd_processor_test.go
+++ b/pkg/proxy/backend/cmd_processor_test.go
@@ -28,40 +28,41 @@ const (
 )
 
 // cmdResponseTypes lists all commands and their responses.
-var cmdResponseTypes = map[byte][]respondType{
-	mysql.ComSleep:            {responseTypeErr},
-	mysql.ComQuit:             {responseTypeNone},
-	mysql.ComInitDB:           {responseTypeOK, responseTypeErr},
-	mysql.ComQuery:            {responseTypeOK, responseTypeErr, responseTypeResultSet, responseTypeLoadFile},
-	mysql.ComFieldList:        {responseTypeErr, responseTypeColumn},
-	mysql.ComCreateDB:         {responseTypeOK, responseTypeErr},
-	mysql.ComDropDB:           {responseTypeOK, responseTypeErr},
-	mysql.ComRefresh:          {responseTypeOK, responseTypeErr},
-	mysql.ComShutdown:         {responseTypeOK, responseTypeErr},
-	mysql.ComStatistics:       {responseTypeString},
-	mysql.ComProcessInfo:      {responseTypeErr, responseTypeResultSet},
-	mysql.ComConnect:          {responseTypeErr},
-	mysql.ComProcessKill:      {responseTypeOK, responseTypeErr},
-	mysql.ComDebug:            {responseTypeEOF, responseTypeErr},
-	mysql.ComPing:             {responseTypeOK},
-	mysql.ComTime:             {responseTypeErr},
-	mysql.ComDelayedInsert:    {responseTypeErr},
-	mysql.ComChangeUser:       {responseTypeSwitchRequest, responseTypeOK, responseTypeErr},
-	mysql.ComBinlogDump:       {responseTypeErr},
-	mysql.ComTableDump:        {responseTypeErr},
-	mysql.ComConnectOut:       {responseTypeErr},
-	mysql.ComRegisterSlave:    {responseTypeErr},
-	mysql.ComStmtPrepare:      {responseTypePrepareOK, responseTypeErr},
-	mysql.ComStmtExecute:      {responseTypeOK, responseTypeErr, responseTypeResultSet},
-	mysql.ComStmtSendLongData: {responseTypeNone},
-	mysql.ComStmtClose:        {responseTypeNone},
-	mysql.ComStmtReset:        {responseTypeOK, responseTypeErr},
-	mysql.ComSetOption:        {responseTypeEOF, responseTypeErr},
-	mysql.ComStmtFetch:        {responseTypeRow, responseTypeErr},
-	mysql.ComDaemon:           {responseTypeErr},
-	mysql.ComBinlogDumpGtid:   {responseTypeErr},
-	mysql.ComResetConnection:  {responseTypeOK, responseTypeErr},
-	mysql.ComEnd:              {responseTypeErr},
+var cmdResponseTypes = map[pnet.Command][]respondType{
+	pnet.ComSleep:     {responseTypeErr},
+	pnet.ComQuit:      {responseTypeNone},
+	pnet.ComInitDB:    {responseTypeOK, responseTypeErr},
+	pnet.ComQuery:     {responseTypeOK, responseTypeErr, responseTypeResultSet, responseTypeLoadFile},
+	pnet.ComFieldList: {responseTypeErr, responseTypeColumn},
+	pnet.ComCreateDB:  {responseTypeOK, responseTypeErr},
+	pnet.ComDropDB:    {responseTypeOK, responseTypeErr},
+	pnet.ComRefresh:   {responseTypeOK, responseTypeErr},
+	// It is comShutdown
+	pnet.ComDeprecated1:      {responseTypeOK, responseTypeErr},
+	pnet.ComStatistics:       {responseTypeString},
+	pnet.ComProcessInfo:      {responseTypeErr, responseTypeResultSet},
+	pnet.ComConnect:          {responseTypeErr},
+	pnet.ComProcessKill:      {responseTypeOK, responseTypeErr},
+	pnet.ComDebug:            {responseTypeEOF, responseTypeErr},
+	pnet.ComPing:             {responseTypeOK},
+	pnet.ComTime:             {responseTypeErr},
+	pnet.ComDelayedInsert:    {responseTypeErr},
+	pnet.ComChangeUser:       {responseTypeSwitchRequest, responseTypeOK, responseTypeErr},
+	pnet.ComBinlogDump:       {responseTypeErr},
+	pnet.ComTableDump:        {responseTypeErr},
+	pnet.ComConnectOut:       {responseTypeErr},
+	pnet.ComRegisterSlave:    {responseTypeErr},
+	pnet.ComStmtPrepare:      {responseTypePrepareOK, responseTypeErr},
+	pnet.ComStmtExecute:      {responseTypeOK, responseTypeErr, responseTypeResultSet},
+	pnet.ComStmtSendLongData: {responseTypeNone},
+	pnet.ComStmtClose:        {responseTypeNone},
+	pnet.ComStmtReset:        {responseTypeOK, responseTypeErr},
+	pnet.ComSetOption:        {responseTypeEOF, responseTypeErr},
+	pnet.ComStmtFetch:        {responseTypeRow, responseTypeErr},
+	pnet.ComDaemon:           {responseTypeErr},
+	pnet.ComBinlogDumpGtid:   {responseTypeErr},
+	pnet.ComResetConnection:  {responseTypeOK, responseTypeErr},
+	pnet.ComEnd:              {responseTypeErr},
 }
 
 // Test forwarding packets between the client and the backend.
@@ -190,7 +191,7 @@ func TestPreparedStmts(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtPrepare
+					cfg.clientConfig.cmd = pnet.ComStmtPrepare
 					cfg.backendConfig.respondType = responseTypePrepareOK
 				},
 			},
@@ -200,7 +201,7 @@ func TestPreparedStmts(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtSendLongData
+					cfg.clientConfig.cmd = pnet.ComStmtSendLongData
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.respondType = responseTypeNone
 				},
@@ -211,12 +212,12 @@ func TestPreparedStmts(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtSendLongData
+					cfg.clientConfig.cmd = pnet.ComStmtSendLongData
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.respondType = responseTypeNone
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtExecute
+					cfg.clientConfig.cmd = pnet.ComStmtExecute
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.columns = 1
 					cfg.backendConfig.respondType = responseTypeResultSet
@@ -227,12 +228,12 @@ func TestPreparedStmts(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtSendLongData
+					cfg.clientConfig.cmd = pnet.ComStmtSendLongData
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.respondType = responseTypeNone
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtExecute
+					cfg.clientConfig.cmd = pnet.ComStmtExecute
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.respondType = responseTypeOK
 				},
@@ -242,12 +243,12 @@ func TestPreparedStmts(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtSendLongData
+					cfg.clientConfig.cmd = pnet.ComStmtSendLongData
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.respondType = responseTypeNone
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtExecute
+					cfg.clientConfig.cmd = pnet.ComStmtExecute
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.respondType = responseTypeErr
 				},
@@ -257,12 +258,12 @@ func TestPreparedStmts(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtSendLongData
+					cfg.clientConfig.cmd = pnet.ComStmtSendLongData
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.respondType = responseTypeNone
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtExecute
+					cfg.clientConfig.cmd = pnet.ComStmtExecute
 					cfg.clientConfig.prepStmtID = 2
 					cfg.backendConfig.respondType = responseTypeOK
 				},
@@ -272,17 +273,17 @@ func TestPreparedStmts(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtSendLongData
+					cfg.clientConfig.cmd = pnet.ComStmtSendLongData
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.respondType = responseTypeNone
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtSendLongData
+					cfg.clientConfig.cmd = pnet.ComStmtSendLongData
 					cfg.clientConfig.prepStmtID = 2
 					cfg.backendConfig.respondType = responseTypeNone
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtExecute
+					cfg.clientConfig.cmd = pnet.ComStmtExecute
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.respondType = responseTypeOK
 				},
@@ -292,12 +293,12 @@ func TestPreparedStmts(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtSendLongData
+					cfg.clientConfig.cmd = pnet.ComStmtSendLongData
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.respondType = responseTypeNone
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtExecute
+					cfg.clientConfig.cmd = pnet.ComStmtExecute
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.columns = 1
 					cfg.backendConfig.respondType = responseTypeResultSet
@@ -310,7 +311,7 @@ func TestPreparedStmts(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtExecute
+					cfg.clientConfig.cmd = pnet.ComStmtExecute
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.columns = 1
 					cfg.backendConfig.respondType = responseTypeResultSet
@@ -322,14 +323,14 @@ func TestPreparedStmts(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtExecute
+					cfg.clientConfig.cmd = pnet.ComStmtExecute
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.columns = 1
 					cfg.backendConfig.respondType = responseTypeResultSet
 					cfg.backendConfig.status = mysql.ServerStatusCursorExists
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtFetch
+					cfg.clientConfig.cmd = pnet.ComStmtFetch
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.respondType = responseTypeRow
 					cfg.backendConfig.status = mysql.ServerStatusCursorExists
@@ -340,14 +341,14 @@ func TestPreparedStmts(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtExecute
+					cfg.clientConfig.cmd = pnet.ComStmtExecute
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.columns = 1
 					cfg.backendConfig.respondType = responseTypeResultSet
 					cfg.backendConfig.status = mysql.ServerStatusCursorExists
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtFetch
+					cfg.clientConfig.cmd = pnet.ComStmtFetch
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.respondType = responseTypeRow
 					cfg.backendConfig.status = mysql.ServerStatusLastRowSend
@@ -358,14 +359,14 @@ func TestPreparedStmts(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtExecute
+					cfg.clientConfig.cmd = pnet.ComStmtExecute
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.columns = 1
 					cfg.backendConfig.respondType = responseTypeResultSet
 					cfg.backendConfig.status = mysql.ServerStatusCursorExists
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtFetch
+					cfg.clientConfig.cmd = pnet.ComStmtFetch
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.respondType = responseTypeErr
 				},
@@ -375,21 +376,21 @@ func TestPreparedStmts(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtExecute
+					cfg.clientConfig.cmd = pnet.ComStmtExecute
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.columns = 1
 					cfg.backendConfig.respondType = responseTypeResultSet
 					cfg.backendConfig.status = mysql.ServerStatusCursorExists
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtExecute
+					cfg.clientConfig.cmd = pnet.ComStmtExecute
 					cfg.clientConfig.prepStmtID = 2
 					cfg.backendConfig.columns = 1
 					cfg.backendConfig.respondType = responseTypeResultSet
 					cfg.backendConfig.status = mysql.ServerStatusCursorExists
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtFetch
+					cfg.clientConfig.cmd = pnet.ComStmtFetch
 					cfg.clientConfig.prepStmtID = 2
 					cfg.backendConfig.respondType = responseTypeRow
 					cfg.backendConfig.status = mysql.ServerStatusLastRowSend
@@ -400,19 +401,19 @@ func TestPreparedStmts(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtSendLongData
+					cfg.clientConfig.cmd = pnet.ComStmtSendLongData
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.respondType = responseTypeNone
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtExecute
+					cfg.clientConfig.cmd = pnet.ComStmtExecute
 					cfg.clientConfig.prepStmtID = 2
 					cfg.backendConfig.columns = 1
 					cfg.backendConfig.respondType = responseTypeResultSet
 					cfg.backendConfig.status = mysql.ServerStatusCursorExists
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtFetch
+					cfg.clientConfig.cmd = pnet.ComStmtFetch
 					cfg.clientConfig.prepStmtID = 2
 					cfg.backendConfig.respondType = responseTypeRow
 					cfg.backendConfig.status = mysql.ServerStatusLastRowSend
@@ -424,12 +425,12 @@ func TestPreparedStmts(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtSendLongData
+					cfg.clientConfig.cmd = pnet.ComStmtSendLongData
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.respondType = responseTypeNone
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtClose
+					cfg.clientConfig.cmd = pnet.ComStmtClose
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.respondType = responseTypeNone
 				},
@@ -439,12 +440,12 @@ func TestPreparedStmts(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtSendLongData
+					cfg.clientConfig.cmd = pnet.ComStmtSendLongData
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.respondType = responseTypeNone
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtClose
+					cfg.clientConfig.cmd = pnet.ComStmtClose
 					cfg.clientConfig.prepStmtID = 2
 					cfg.backendConfig.respondType = responseTypeNone
 				},
@@ -454,12 +455,12 @@ func TestPreparedStmts(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtSendLongData
+					cfg.clientConfig.cmd = pnet.ComStmtSendLongData
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.respondType = responseTypeNone
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtReset
+					cfg.clientConfig.cmd = pnet.ComStmtReset
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.respondType = responseTypeOK
 				},
@@ -469,12 +470,12 @@ func TestPreparedStmts(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtSendLongData
+					cfg.clientConfig.cmd = pnet.ComStmtSendLongData
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.respondType = responseTypeNone
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtReset
+					cfg.clientConfig.cmd = pnet.ComStmtReset
 					cfg.clientConfig.prepStmtID = 2
 					cfg.backendConfig.respondType = responseTypeOK
 				},
@@ -485,14 +486,14 @@ func TestPreparedStmts(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtExecute
+					cfg.clientConfig.cmd = pnet.ComStmtExecute
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.columns = 1
 					cfg.backendConfig.respondType = responseTypeResultSet
 					cfg.backendConfig.status = mysql.ServerStatusCursorExists
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtClose
+					cfg.clientConfig.cmd = pnet.ComStmtClose
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.respondType = responseTypeNone
 				},
@@ -502,14 +503,14 @@ func TestPreparedStmts(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtExecute
+					cfg.clientConfig.cmd = pnet.ComStmtExecute
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.columns = 1
 					cfg.backendConfig.respondType = responseTypeResultSet
 					cfg.backendConfig.status = mysql.ServerStatusCursorExists
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtReset
+					cfg.clientConfig.cmd = pnet.ComStmtReset
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.respondType = responseTypeOK
 				},
@@ -519,14 +520,14 @@ func TestPreparedStmts(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtExecute
+					cfg.clientConfig.cmd = pnet.ComStmtExecute
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.columns = 1
 					cfg.backendConfig.respondType = responseTypeResultSet
 					cfg.backendConfig.status = mysql.ServerStatusCursorExists
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtClose
+					cfg.clientConfig.cmd = pnet.ComStmtClose
 					cfg.clientConfig.prepStmtID = 2
 					cfg.backendConfig.respondType = responseTypeNone
 				},
@@ -536,14 +537,14 @@ func TestPreparedStmts(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtExecute
+					cfg.clientConfig.cmd = pnet.ComStmtExecute
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.columns = 1
 					cfg.backendConfig.respondType = responseTypeResultSet
 					cfg.backendConfig.status = mysql.ServerStatusCursorExists
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtReset
+					cfg.clientConfig.cmd = pnet.ComStmtReset
 					cfg.clientConfig.prepStmtID = 2
 					cfg.backendConfig.respondType = responseTypeOK
 				},
@@ -554,19 +555,19 @@ func TestPreparedStmts(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtSendLongData
+					cfg.clientConfig.cmd = pnet.ComStmtSendLongData
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.respondType = responseTypeNone
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtExecute
+					cfg.clientConfig.cmd = pnet.ComStmtExecute
 					cfg.clientConfig.prepStmtID = 2
 					cfg.backendConfig.columns = 1
 					cfg.backendConfig.respondType = responseTypeResultSet
 					cfg.backendConfig.status = mysql.ServerStatusCursorExists
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComResetConnection
+					cfg.clientConfig.cmd = pnet.ComResetConnection
 					cfg.backendConfig.respondType = responseTypeOK
 				},
 			},
@@ -575,19 +576,19 @@ func TestPreparedStmts(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtSendLongData
+					cfg.clientConfig.cmd = pnet.ComStmtSendLongData
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.respondType = responseTypeNone
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtExecute
+					cfg.clientConfig.cmd = pnet.ComStmtExecute
 					cfg.clientConfig.prepStmtID = 2
 					cfg.backendConfig.columns = 1
 					cfg.backendConfig.respondType = responseTypeResultSet
 					cfg.backendConfig.status = mysql.ServerStatusCursorExists
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComChangeUser
+					cfg.clientConfig.cmd = pnet.ComChangeUser
 					cfg.backendConfig.respondType = responseTypeOK
 				},
 			},
@@ -615,7 +616,7 @@ func TestTxnStatus(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComQuery
+					cfg.clientConfig.cmd = pnet.ComQuery
 					cfg.backendConfig.respondType = responseTypeOK
 					cfg.backendConfig.status = mysql.ServerStatusAutocommit | mysql.ServerStatusInTrans
 				},
@@ -625,7 +626,7 @@ func TestTxnStatus(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComQuery
+					cfg.clientConfig.cmd = pnet.ComQuery
 					cfg.backendConfig.respondType = responseTypeOK
 					cfg.backendConfig.status = mysql.ServerStatusInTrans
 				},
@@ -635,12 +636,12 @@ func TestTxnStatus(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComQuery
+					cfg.clientConfig.cmd = pnet.ComQuery
 					cfg.backendConfig.respondType = responseTypeOK
 					cfg.backendConfig.status = mysql.ServerStatusInTrans
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComQuery
+					cfg.clientConfig.cmd = pnet.ComQuery
 					cfg.backendConfig.respondType = responseTypeOK
 					cfg.backendConfig.status = 0
 				},
@@ -650,12 +651,12 @@ func TestTxnStatus(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComQuery
+					cfg.clientConfig.cmd = pnet.ComQuery
 					cfg.backendConfig.respondType = responseTypeOK
 					cfg.backendConfig.status = mysql.ServerStatusAutocommit | mysql.ServerStatusInTrans
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComQuery
+					cfg.clientConfig.cmd = pnet.ComQuery
 					cfg.backendConfig.respondType = responseTypeOK
 					cfg.backendConfig.status = mysql.ServerStatusAutocommit
 				},
@@ -665,12 +666,12 @@ func TestTxnStatus(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComQuery
+					cfg.clientConfig.cmd = pnet.ComQuery
 					cfg.backendConfig.respondType = responseTypeOK
 					cfg.backendConfig.status = mysql.ServerStatusInTrans
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComChangeUser
+					cfg.clientConfig.cmd = pnet.ComChangeUser
 					cfg.backendConfig.respondType = responseTypeOK
 					cfg.backendConfig.status = mysql.ServerStatusAutocommit
 				},
@@ -680,12 +681,12 @@ func TestTxnStatus(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComQuery
+					cfg.clientConfig.cmd = pnet.ComQuery
 					cfg.backendConfig.respondType = responseTypeOK
 					cfg.backendConfig.status = mysql.ServerStatusInTrans
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComResetConnection
+					cfg.clientConfig.cmd = pnet.ComResetConnection
 					cfg.backendConfig.respondType = responseTypeOK
 					cfg.backendConfig.status = mysql.ServerStatusAutocommit
 				},
@@ -714,12 +715,12 @@ func TestMixPrepAndTxnStatus(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComQuery
+					cfg.clientConfig.cmd = pnet.ComQuery
 					cfg.backendConfig.respondType = responseTypeOK
 					cfg.backendConfig.status = mysql.ServerStatusInTrans
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtExecute
+					cfg.clientConfig.cmd = pnet.ComStmtExecute
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.respondType = responseTypeOK
 					cfg.backendConfig.status = mysql.ServerStatusInTrans
@@ -730,14 +731,14 @@ func TestMixPrepAndTxnStatus(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtExecute
+					cfg.clientConfig.cmd = pnet.ComStmtExecute
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.columns = 1
 					cfg.backendConfig.respondType = responseTypeResultSet
 					cfg.backendConfig.status = mysql.ServerStatusInTrans | mysql.ServerStatusCursorExists
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtFetch
+					cfg.clientConfig.cmd = pnet.ComStmtFetch
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.respondType = responseTypeRow
 					cfg.backendConfig.status = mysql.ServerStatusInTrans | mysql.ServerStatusLastRowSend
@@ -748,14 +749,14 @@ func TestMixPrepAndTxnStatus(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtExecute
+					cfg.clientConfig.cmd = pnet.ComStmtExecute
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.columns = 1
 					cfg.backendConfig.respondType = responseTypeResultSet
 					cfg.backendConfig.status = mysql.ServerStatusInTrans | mysql.ServerStatusCursorExists
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComQuery
+					cfg.clientConfig.cmd = pnet.ComQuery
 					cfg.backendConfig.columns = 1
 					cfg.backendConfig.respondType = responseTypeOK
 					cfg.backendConfig.status = 0
@@ -766,14 +767,14 @@ func TestMixPrepAndTxnStatus(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtExecute
+					cfg.clientConfig.cmd = pnet.ComStmtExecute
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.columns = 1
 					cfg.backendConfig.respondType = responseTypeResultSet
 					cfg.backendConfig.status = mysql.ServerStatusInTrans | mysql.ServerStatusCursorExists
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComResetConnection
+					cfg.clientConfig.cmd = pnet.ComResetConnection
 					cfg.backendConfig.respondType = responseTypeOK
 					cfg.backendConfig.status = mysql.ServerStatusAutocommit
 				},
@@ -783,20 +784,20 @@ func TestMixPrepAndTxnStatus(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtExecute
+					cfg.clientConfig.cmd = pnet.ComStmtExecute
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.columns = 1
 					cfg.backendConfig.respondType = responseTypeResultSet
 					cfg.backendConfig.status = mysql.ServerStatusInTrans | mysql.ServerStatusCursorExists
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtFetch
+					cfg.clientConfig.cmd = pnet.ComStmtFetch
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.respondType = responseTypeRow
 					cfg.backendConfig.status = mysql.ServerStatusInTrans | mysql.ServerStatusLastRowSend
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtExecute
+					cfg.clientConfig.cmd = pnet.ComStmtExecute
 					cfg.clientConfig.prepStmtID = 2
 					cfg.backendConfig.respondType = responseTypeOK
 					cfg.backendConfig.status = 0
@@ -826,12 +827,12 @@ func TestHoldRequest(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComQuery
+					cfg.clientConfig.cmd = pnet.ComQuery
 					cfg.backendConfig.respondType = responseTypeOK
 					cfg.backendConfig.status = mysql.ServerStatusAutocommit | mysql.ServerStatusInTrans
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComQuery
+					cfg.clientConfig.cmd = pnet.ComQuery
 					cfg.clientConfig.sql = "begin"
 					cfg.proxyConfig.waitRedirect = true
 					cfg.backendConfig.respondType = responseTypeOK
@@ -845,12 +846,12 @@ func TestHoldRequest(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComQuery
+					cfg.clientConfig.cmd = pnet.ComQuery
 					cfg.backendConfig.respondType = responseTypeOK
 					cfg.backendConfig.status = mysql.ServerStatusAutocommit | mysql.ServerStatusInTrans
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComQuery
+					cfg.clientConfig.cmd = pnet.ComQuery
 					cfg.clientConfig.sql = "commit"
 					cfg.proxyConfig.waitRedirect = true
 					cfg.backendConfig.respondType = responseTypeOK
@@ -863,12 +864,12 @@ func TestHoldRequest(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComQuery
+					cfg.clientConfig.cmd = pnet.ComQuery
 					cfg.backendConfig.respondType = responseTypeOK
 					cfg.backendConfig.status = mysql.ServerStatusAutocommit | mysql.ServerStatusInTrans
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtExecute
+					cfg.clientConfig.cmd = pnet.ComStmtExecute
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.columns = 1
 					cfg.backendConfig.respondType = responseTypeOK
@@ -881,19 +882,19 @@ func TestHoldRequest(t *testing.T) {
 		{
 			cfgs: []cfgOverrider{
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComQuery
+					cfg.clientConfig.cmd = pnet.ComQuery
 					cfg.backendConfig.respondType = responseTypeOK
 					cfg.backendConfig.status = mysql.ServerStatusAutocommit | mysql.ServerStatusInTrans
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComStmtExecute
+					cfg.clientConfig.cmd = pnet.ComStmtExecute
 					cfg.clientConfig.prepStmtID = 1
 					cfg.backendConfig.columns = 1
 					cfg.backendConfig.respondType = responseTypeResultSet
 					cfg.backendConfig.status = mysql.ServerStatusCursorExists
 				},
 				func(cfg *testConfig) {
-					cfg.clientConfig.cmd = mysql.ComQuery
+					cfg.clientConfig.cmd = pnet.ComQuery
 					cfg.clientConfig.sql = "begin"
 					cfg.proxyConfig.waitRedirect = true
 					cfg.backendConfig.respondType = responseTypeOK
@@ -976,31 +977,31 @@ func TestMultiStmt(t *testing.T) {
 	// COM_STMT_PREPARE don't support multiple statements, so we only test COM_QUERY.
 	cfgs := []cfgOverrider{
 		func(cfg *testConfig) {
-			cfg.clientConfig.cmd = mysql.ComQuery
+			cfg.clientConfig.cmd = pnet.ComQuery
 			cfg.backendConfig.respondType = responseTypeOK
 			cfg.backendConfig.stmtNum = 2
 		},
 		func(cfg *testConfig) {
-			cfg.clientConfig.cmd = mysql.ComQuery
+			cfg.clientConfig.cmd = pnet.ComQuery
 			cfg.backendConfig.respondType = responseTypeResultSet
 			cfg.backendConfig.columns = 1
 			cfg.backendConfig.stmtNum = 2
 		},
 		func(cfg *testConfig) {
-			cfg.clientConfig.cmd = mysql.ComQuery
+			cfg.clientConfig.cmd = pnet.ComQuery
 			cfg.backendConfig.respondType = responseTypeResultSet
 			cfg.backendConfig.columns = 1
 			cfg.backendConfig.rows = 1
 			cfg.backendConfig.stmtNum = 2
 		},
 		func(cfg *testConfig) {
-			cfg.clientConfig.cmd = mysql.ComQuery
+			cfg.clientConfig.cmd = pnet.ComQuery
 			cfg.backendConfig.respondType = responseTypeResultSet
 			cfg.backendConfig.columns = 1
 			cfg.backendConfig.stmtNum = 3
 		},
 		func(cfg *testConfig) {
-			cfg.clientConfig.cmd = mysql.ComQuery
+			cfg.clientConfig.cmd = pnet.ComQuery
 			cfg.backendConfig.respondType = responseTypeLoadFile
 			cfg.backendConfig.stmtNum = 2
 		},
diff --git a/pkg/proxy/backend/metrics.go b/pkg/proxy/backend/metrics.go
index 2f3a683b..50582937 100644
--- a/pkg/proxy/backend/metrics.go
+++ b/pkg/proxy/backend/metrics.go
@@ -10,8 +10,8 @@ import (
 	pnet "github.com/pingcap/TiProxy/pkg/proxy/net"
 )
 
-func addCmdMetrics(cmd byte, addr string, startTime time.Time) {
-	label := pnet.Command(cmd).String()
+func addCmdMetrics(cmd pnet.Command, addr string, startTime time.Time) {
+	label := cmd.String()
 	metrics.QueryTotalCounter.WithLabelValues(addr, label).Inc()
 
 	// The duration labels are different with TiDB: Labels in TiDB are statement types.
@@ -20,8 +20,8 @@ func addCmdMetrics(cmd byte, addr string, startTime time.Time) {
 	metrics.QueryDurationHistogram.WithLabelValues(addr, label).Observe(cost.Seconds())
 }
 
-func readCmdCounter(cmd byte, addr string) (int, error) {
-	label := pnet.Command(cmd).String()
+func readCmdCounter(cmd pnet.Command, addr string) (int, error) {
+	label := cmd.String()
 	return metrics.ReadCounter(metrics.QueryTotalCounter.WithLabelValues(addr, label))
 }
 
diff --git a/pkg/proxy/backend/mock_backend_test.go b/pkg/proxy/backend/mock_backend_test.go
index 15742637..53b39ffd 100644
--- a/pkg/proxy/backend/mock_backend_test.go
+++ b/pkg/proxy/backend/mock_backend_test.go
@@ -152,7 +152,7 @@ func (mb *mockBackend) respondOnce(packetIO *pnet.PacketIO) error {
 	case responseTypeErr:
 		return packetIO.WriteErrPacket(mysql.NewErr(mysql.ErrUnknown))
 	case responseTypeResultSet:
-		if pkt[0] == mysql.ComQuery && string(pkt[1:]) == sqlQueryState {
+		if pnet.Command(pkt[0]) == pnet.ComQuery && string(pkt[1:]) == sqlQueryState {
 			return mb.respondSessionStates(packetIO)
 		}
 		return mb.respondResultSet(packetIO)
diff --git a/pkg/proxy/backend/mock_client_test.go b/pkg/proxy/backend/mock_client_test.go
index 491fc554..ef0ff03f 100644
--- a/pkg/proxy/backend/mock_client_test.go
+++ b/pkg/proxy/backend/mock_client_test.go
@@ -25,8 +25,7 @@ type clientConfig struct {
 	prepStmtID int
 	capability pnet.Capability
 	collation  uint8
-	// for cmd
-	cmd byte
+	cmd        pnet.Command
 	// for both auth and cmd
 	abnormalExit bool
 }
@@ -39,7 +38,7 @@ func newClientConfig() *clientConfig {
 		authPlugin: mysql.AuthCachingSha2Password,
 		authData:   mockAuthData,
 		attrs:      make(map[string]string),
-		cmd:        mysql.ComQuery,
+		cmd:        pnet.ComQuery,
 		dataBytes:  mockCmdBytes,
 		sql:        mockCmdStr,
 	}
@@ -125,39 +124,39 @@ func (mc *mockClient) request(packetIO *pnet.PacketIO) error {
 		return packetIO.Close()
 	}
 	packetIO.ResetSequence()
-	data := []byte{mc.cmd}
+	data := []byte{mc.cmd.Byte()}
 	switch mc.cmd {
-	case mysql.ComInitDB, mysql.ComCreateDB, mysql.ComDropDB:
+	case pnet.ComInitDB, pnet.ComCreateDB, pnet.ComDropDB:
 		data = append(data, []byte(mockCmdStr)...)
-	case mysql.ComQuery:
+	case pnet.ComQuery:
 		return mc.query(packetIO)
-	case mysql.ComProcessInfo:
+	case pnet.ComProcessInfo:
 		return mc.requestProcessInfo(packetIO)
-	case mysql.ComFieldList:
+	case pnet.ComFieldList:
 		return mc.requestFieldList(packetIO)
-	case mysql.ComRefresh, mysql.ComSetOption:
+	case pnet.ComRefresh, pnet.ComSetOption:
 		data = append(data, mc.dataBytes...)
-	case mysql.ComProcessKill:
+	case pnet.ComProcessKill:
 		data = pnet.DumpUint32(data, uint32(mockCmdInt))
-	case mysql.ComChangeUser:
+	case pnet.ComChangeUser:
 		return mc.requestChangeUser(packetIO)
-	case mysql.ComStmtPrepare:
+	case pnet.ComStmtPrepare:
 		return mc.requestPrepare(packetIO)
-	case mysql.ComStmtSendLongData:
+	case pnet.ComStmtSendLongData:
 		data = pnet.DumpUint32(data, uint32(mc.prepStmtID))
 		data = append(data, mc.dataBytes...)
-	case mysql.ComStmtExecute:
+	case pnet.ComStmtExecute:
 		return mc.requestExecute(packetIO)
-	case mysql.ComStmtFetch:
+	case pnet.ComStmtFetch:
 		return mc.requestFetch(packetIO)
-	case mysql.ComStmtClose, mysql.ComStmtReset:
+	case pnet.ComStmtClose, pnet.ComStmtReset:
 		data = pnet.DumpUint32(data, uint32(mc.prepStmtID))
 	}
 	if err := packetIO.WritePacket(data, true); err != nil {
 		return err
 	}
 	switch mc.cmd {
-	case mysql.ComQuit, mysql.ComStmtClose, mysql.ComStmtSendLongData:
+	case pnet.ComQuit, pnet.ComStmtClose, pnet.ComStmtSendLongData:
 		return nil
 	}
 	_, err := packetIO.ReadPacket()
@@ -190,7 +189,7 @@ func (mc *mockClient) requestChangeUser(packetIO *pnet.PacketIO) error {
 
 func (mc *mockClient) requestPrepare(packetIO *pnet.PacketIO) error {
 	data := make([]byte, 0, len(mc.sql)+1)
-	data = append(data, mysql.ComStmtPrepare)
+	data = append(data, pnet.ComStmtPrepare.Byte())
 	data = append(data, []byte(mc.sql)...)
 	if err := packetIO.WritePacket(data, true); err != nil {
 		return err
@@ -223,7 +222,7 @@ func (mc *mockClient) requestPrepare(packetIO *pnet.PacketIO) error {
 
 func (mc *mockClient) requestExecute(packetIO *pnet.PacketIO) error {
 	data := make([]byte, 0, len(mc.dataBytes)+5)
-	data = append(data, mysql.ComStmtExecute)
+	data = append(data, pnet.ComStmtExecute.Byte())
 	data = pnet.DumpUint32(data, uint32(mc.prepStmtID))
 	data = append(data, mc.dataBytes...)
 	if err := packetIO.WritePacket(data, true); err != nil {
@@ -234,7 +233,7 @@ func (mc *mockClient) requestExecute(packetIO *pnet.PacketIO) error {
 
 func (mc *mockClient) requestFetch(packetIO *pnet.PacketIO) error {
 	data := make([]byte, 0, len(mc.dataBytes)+5)
-	data = append(data, mysql.ComStmtFetch)
+	data = append(data, pnet.ComStmtFetch.Byte())
 	data = pnet.DumpUint32(data, uint32(mc.prepStmtID))
 	data = append(data, mc.dataBytes...)
 	if err := packetIO.WritePacket(data, true); err != nil {
@@ -246,7 +245,7 @@ func (mc *mockClient) requestFetch(packetIO *pnet.PacketIO) error {
 
 func (mc *mockClient) requestFieldList(packetIO *pnet.PacketIO) error {
 	data := make([]byte, 0, len(mockCmdStr)+2)
-	data = append(data, mysql.ComFieldList)
+	data = append(data, pnet.ComFieldList.Byte())
 	data = append(data, []byte(mockCmdStr)...)
 	data = append(data, 0x00)
 	data = append(data, []byte(mockCmdStr)...)
@@ -281,7 +280,7 @@ func (mc *mockClient) readUntilResultEnd(packetIO *pnet.PacketIO) (pkt []byte, e
 }
 
 func (mc *mockClient) requestProcessInfo(packetIO *pnet.PacketIO) error {
-	if err := packetIO.WritePacket([]byte{mysql.ComProcessInfo}, true); err != nil {
+	if err := packetIO.WritePacket([]byte{pnet.ComProcessInfo.Byte()}, true); err != nil {
 		return err
 	}
 	return mc.readResultSet(packetIO)
@@ -289,7 +288,7 @@ func (mc *mockClient) requestProcessInfo(packetIO *pnet.PacketIO) error {
 
 func (mc *mockClient) query(packetIO *pnet.PacketIO) error {
 	data := make([]byte, 0, len(mc.sql)+1)
-	data = append(data, mysql.ComQuery)
+	data = append(data, pnet.ComQuery.Byte())
 	data = append(data, []byte(mc.sql)...)
 	if err := packetIO.WritePacket(data, true); err != nil {
 		return err
diff --git a/pkg/proxy/net/mysql.go b/pkg/proxy/net/mysql.go
index 2ee75aa5..781ca17c 100644
--- a/pkg/proxy/net/mysql.go
+++ b/pkg/proxy/net/mysql.go
@@ -252,7 +252,7 @@ func MakeHandshakeResponse(resp *HandshakeResp) []byte {
 func MakeChangeUser(username, db, authPlugin string, authData []byte) []byte {
 	length := 1 + len(username) + 1 + len(authData) + 1 + len(db) + 1
 	data := make([]byte, 0, length)
-	data = append(data, mysql.ComChangeUser)
+	data = append(data, ComChangeUser.Byte())
 	data = append(data, []byte(username)...)
 	data = append(data, 0x00)
 	data = append(data, byte(len(authData)))