for #1941, remove generic for CommandExecutor

sharding-proxy/sharding-proxy-frontend/sharding-proxy-frontend-mysql/src/main/java/org/apache/shardingsphere/shardingproxy/frontend/mysql/MySQLFrontendEngine.java

@@ -37,7 +37,6 @@ import org.apache.shardingsphere.shardingproxy.transport.api.packet.CommandPacke
 import org.apache.shardingsphere.shardingproxy.transport.api.packet.DatabasePacket;
 import org.apache.shardingsphere.shardingproxy.transport.api.payload.PacketPayload;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.constant.MySQLServerErrorCode;
-import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.MySQLPacket;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.command.MySQLCommandPacket;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.command.MySQLCommandPacketFactory;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.command.MySQLCommandPacketType;
@@ -67,7 +66,7 @@ import java.util.Collection;
 @Slf4j
 public final class MySQLFrontendEngine implements DatabaseFrontendEngine {
     
-    private final MySQLAuthenticationHandler mysqlAuthenticationHandler = new MySQLAuthenticationHandler();
+    private final MySQLAuthenticationHandler authenticationHandler = new MySQLAuthenticationHandler();
     
     @Override
     public PacketPayload createPacketPayload(final ByteBuf message) {
@@ -88,14 +87,14 @@ public final class MySQLFrontendEngine implements DatabaseFrontendEngine {
     public void handshake(final ChannelHandlerContext context, final BackendConnection backendConnection) {
         int connectionId = MySQLConnectionIdGenerator.getInstance().nextId();
         backendConnection.setConnectionId(connectionId);
-        context.writeAndFlush(new MySQLHandshakePacket(connectionId, mysqlAuthenticationHandler.getAuthPluginData()));
+        context.writeAndFlush(new MySQLHandshakePacket(connectionId, authenticationHandler.getAuthPluginData()));
     }
     
     @Override
     public boolean auth(final ChannelHandlerContext context, final ByteBuf message, final BackendConnection backendConnection) {
         try (MySQLPacketPayload payload = new MySQLPacketPayload(message)) {
             MySQLHandshakeResponse41Packet response41 = new MySQLHandshakeResponse41Packet(payload);
-            if (mysqlAuthenticationHandler.login(response41.getUsername(), response41.getAuthResponse())) {
+            if (authenticationHandler.login(response41.getUsername(), response41.getAuthResponse())) {
                 if (!Strings.isNullOrEmpty(response41.getDatabase()) && !LogicSchemas.getInstance().schemaExists(response41.getDatabase())) {
                     context.writeAndFlush(new MySQLErrPacket(response41.getSequenceId() + 1, MySQLServerErrorCode.ER_BAD_DB_ERROR, response41.getDatabase()));
                     return true;
@@ -122,7 +121,7 @@ public final class MySQLFrontendEngine implements DatabaseFrontendEngine {
     }
     
     @Override
-    public CommandExecutor<MySQLPacket> getCommandExecutor(final CommandPacketType type, final CommandPacket packet, final BackendConnection backendConnection) {
+    public CommandExecutor getCommandExecutor(final CommandPacketType type, final CommandPacket packet, final BackendConnection backendConnection) {
         return MySQLCommandExecutorFactory.newInstance((MySQLCommandPacketType) type, packet, backendConnection);
     }
     
@@ -144,24 +143,24 @@ public final class MySQLFrontendEngine implements DatabaseFrontendEngine {
     }
     
     private void writePackets(final ChannelHandlerContext context, final MySQLPacketPayload payload, final BackendConnection backendConnection) throws SQLException {
-        MySQLCommandPacketType type = getCommandPacketType(payload);
-        MySQLCommandPacket commandPacket = getCommandPacket(payload, type, backendConnection);
-        CommandExecutor<MySQLPacket> commandExecutor = getCommandExecutor(type, commandPacket, backendConnection);
-        Collection<MySQLPacket> responsePackets = commandExecutor.execute();
+        CommandPacketType type = getCommandPacketType(payload);
+        CommandPacket commandPacket = getCommandPacket(payload, type, backendConnection);
+        CommandExecutor commandExecutor = getCommandExecutor(type, commandPacket, backendConnection);
+        Collection<DatabasePacket> responsePackets = commandExecutor.execute();
         if (responsePackets.isEmpty()) {
             return;
         }
-        for (MySQLPacket each : responsePackets) {
+        for (DatabasePacket each : responsePackets) {
             context.write(each);
         }
         if (commandExecutor instanceof QueryCommandExecutor) {
-            writeQueryData(context, backendConnection, (QueryCommandExecutor<MySQLPacket>) commandExecutor, responsePackets.size());
+            writeQueryData(context, backendConnection, (QueryCommandExecutor) commandExecutor, responsePackets.size());
         }
     }
     
     @Override
     public void writeQueryData(final ChannelHandlerContext context, 
-                               final BackendConnection backendConnection, final QueryCommandExecutor<?> queryCommandExecutor, final int sequenceIdOffset) throws SQLException {
+                               final BackendConnection backendConnection, final QueryCommandExecutor queryCommandExecutor, final int headerPackagesCount) throws SQLException {
         if (!queryCommandExecutor.isQuery() || !context.channel().isActive()) {
             return;
         }
@@ -182,7 +181,7 @@ public final class MySQLFrontendEngine implements DatabaseFrontendEngine {
             }
             currentSequenceId++;
         }
-        context.write(new MySQLEofPacket(++currentSequenceId + sequenceIdOffset));
+        context.write(new MySQLEofPacket(++currentSequenceId + headerPackagesCount));
     }
     
     @Override

sharding-proxy/sharding-proxy-frontend/sharding-proxy-frontend-mysql/src/main/java/org/apache/shardingsphere/shardingproxy/frontend/mysql/executor/MySQLCommandExecutorFactory.java

@@ -31,7 +31,6 @@ import org.apache.shardingsphere.shardingproxy.frontend.mysql.executor.query.bin
 import org.apache.shardingsphere.shardingproxy.frontend.mysql.executor.query.text.fieldlist.MySQLComFieldListPacketExecutor;
 import org.apache.shardingsphere.shardingproxy.frontend.mysql.executor.query.text.query.MySQLComQueryPacketExecutor;
 import org.apache.shardingsphere.shardingproxy.transport.api.packet.CommandPacket;
-import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.MySQLPacket;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.command.MySQLCommandPacketType;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.command.admin.initdb.MySQLComInitDbPacket;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.command.query.binary.close.MySQLComStmtClosePacket;
@@ -56,7 +55,7 @@ public final class MySQLCommandExecutorFactory {
      * @param backendConnection backend connection
      * @return command executor
      */
-    public static CommandExecutor<MySQLPacket> newInstance(final MySQLCommandPacketType commandPacketType, final CommandPacket commandPacket, final BackendConnection backendConnection) {
+    public static CommandExecutor newInstance(final MySQLCommandPacketType commandPacketType, final CommandPacket commandPacket, final BackendConnection backendConnection) {
         switch (commandPacketType) {
             case COM_QUIT:
                 return new MySQLComQuitExecutor();

sharding-proxy/sharding-proxy-frontend/sharding-proxy-frontend-mysql/src/main/java/org/apache/shardingsphere/shardingproxy/frontend/mysql/executor/admin/initdb/MySQLComInitDbExecutor.java

@@ -21,8 +21,8 @@ import lombok.RequiredArgsConstructor;
 import org.apache.shardingsphere.shardingproxy.backend.communication.jdbc.connection.BackendConnection;
 import org.apache.shardingsphere.shardingproxy.backend.schema.LogicSchemas;
 import org.apache.shardingsphere.shardingproxy.frontend.api.CommandExecutor;
+import org.apache.shardingsphere.shardingproxy.transport.api.packet.DatabasePacket;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.constant.MySQLServerErrorCode;
-import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.MySQLPacket;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.command.admin.initdb.MySQLComInitDbPacket;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.generic.MySQLErrPacket;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.generic.MySQLOKPacket;
@@ -36,18 +36,18 @@ import java.util.Collections;
  * @author zhangliang
  */
 @RequiredArgsConstructor
-public final class MySQLComInitDbExecutor implements CommandExecutor<MySQLPacket> {
+public final class MySQLComInitDbExecutor implements CommandExecutor {
     
     private final MySQLComInitDbPacket packet;
     
     private final BackendConnection backendConnection;
     
     @Override
-    public Collection<MySQLPacket> execute() {
+    public Collection<DatabasePacket> execute() {
         if (LogicSchemas.getInstance().schemaExists(packet.getSchema())) {
             backendConnection.setCurrentSchema(packet.getSchema());
-            return Collections.<MySQLPacket>singletonList(new MySQLOKPacket(1));
+            return Collections.<DatabasePacket>singletonList(new MySQLOKPacket(1));
         }
-        return Collections.<MySQLPacket>singletonList(new MySQLErrPacket(1, MySQLServerErrorCode.ER_BAD_DB_ERROR, packet.getSchema()));
+        return Collections.<DatabasePacket>singletonList(new MySQLErrPacket(1, MySQLServerErrorCode.ER_BAD_DB_ERROR, packet.getSchema()));
     }
 }

sharding-proxy/sharding-proxy-frontend/sharding-proxy-frontend-mysql/src/main/java/org/apache/shardingsphere/shardingproxy/frontend/mysql/executor/admin/ping/MySQLComPingExecutor.java

@@ -17,9 +17,8 @@
 
 package org.apache.shardingsphere.shardingproxy.frontend.mysql.executor.admin.ping;
 
-import lombok.RequiredArgsConstructor;
 import org.apache.shardingsphere.shardingproxy.frontend.api.CommandExecutor;
-import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.MySQLPacket;
+import org.apache.shardingsphere.shardingproxy.transport.api.packet.DatabasePacket;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.generic.MySQLOKPacket;
 
 import java.util.Collection;
@@ -30,11 +29,10 @@ import java.util.Collections;
  *
  * @author zhangliang
  */
-@RequiredArgsConstructor
-public final class MySQLComPingExecutor implements CommandExecutor<MySQLPacket> {
+public final class MySQLComPingExecutor implements CommandExecutor {
     
     @Override
-    public Collection<MySQLPacket> execute() {
-        return Collections.<MySQLPacket>singletonList(new MySQLOKPacket(1));
+    public Collection<DatabasePacket> execute() {
+        return Collections.<DatabasePacket>singletonList(new MySQLOKPacket(1));
     }
 }

sharding-proxy/sharding-proxy-frontend/sharding-proxy-frontend-mysql/src/main/java/org/apache/shardingsphere/shardingproxy/frontend/mysql/executor/admin/quit/MySQLComQuitExecutor.java

@@ -17,9 +17,8 @@
 
 package org.apache.shardingsphere.shardingproxy.frontend.mysql.executor.admin.quit;
 
-import lombok.RequiredArgsConstructor;
 import org.apache.shardingsphere.shardingproxy.frontend.api.CommandExecutor;
-import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.MySQLPacket;
+import org.apache.shardingsphere.shardingproxy.transport.api.packet.DatabasePacket;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.generic.MySQLOKPacket;
 
 import java.util.Collection;
@@ -30,11 +29,10 @@ import java.util.Collections;
  *
  * @author zhangliang
  */
-@RequiredArgsConstructor
-public final class MySQLComQuitExecutor implements CommandExecutor<MySQLPacket> {
+public final class MySQLComQuitExecutor implements CommandExecutor {
     
     @Override
-    public Collection<MySQLPacket> execute() {
-        return Collections.<MySQLPacket>singletonList(new MySQLOKPacket(1));
+    public Collection<DatabasePacket> execute() {
+        return Collections.<DatabasePacket>singletonList(new MySQLOKPacket(1));
     }
 }

sharding-proxy/sharding-proxy-frontend/sharding-proxy-frontend-mysql/src/main/java/org/apache/shardingsphere/shardingproxy/frontend/mysql/executor/generic/MySQLUnsupportedCommandExecutor.java

@@ -20,7 +20,7 @@ package org.apache.shardingsphere.shardingproxy.frontend.mysql.executor.generic;
 import lombok.RequiredArgsConstructor;
 import org.apache.shardingsphere.shardingproxy.error.CommonErrorCode;
 import org.apache.shardingsphere.shardingproxy.frontend.api.CommandExecutor;
-import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.MySQLPacket;
+import org.apache.shardingsphere.shardingproxy.transport.api.packet.DatabasePacket;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.command.MySQLCommandPacketType;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.generic.MySQLErrPacket;
 
@@ -33,12 +33,12 @@ import java.util.Collections;
  * @author zhangliang
  */
 @RequiredArgsConstructor
-public final class MySQLUnsupportedCommandExecutor implements CommandExecutor<MySQLPacket> {
+public final class MySQLUnsupportedCommandExecutor implements CommandExecutor {
     
     private final MySQLCommandPacketType type;
     
     @Override
-    public Collection<MySQLPacket> execute() {
-        return Collections.<MySQLPacket>singletonList(new MySQLErrPacket(1, CommonErrorCode.UNSUPPORTED_COMMAND, type));
+    public Collection<DatabasePacket> execute() {
+        return Collections.<DatabasePacket>singletonList(new MySQLErrPacket(1, CommonErrorCode.UNSUPPORTED_COMMAND, type));
     }
 }

sharding-proxy/sharding-proxy-frontend/sharding-proxy-frontend-mysql/src/main/java/org/apache/shardingsphere/shardingproxy/frontend/mysql/executor/query/binary/close/MySQLComStmtCloseExecutor.java

@@ -19,7 +19,7 @@ package org.apache.shardingsphere.shardingproxy.frontend.mysql.executor.query.bi
 
 import lombok.RequiredArgsConstructor;
 import org.apache.shardingsphere.shardingproxy.frontend.api.CommandExecutor;
-import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.MySQLPacket;
+import org.apache.shardingsphere.shardingproxy.transport.api.packet.DatabasePacket;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.command.query.binary.close.MySQLComStmtClosePacket;
 
 import java.util.Collection;
@@ -31,12 +31,12 @@ import java.util.Collections;
  * @author zhangliang
  */
 @RequiredArgsConstructor
-public final class MySQLComStmtCloseExecutor implements CommandExecutor<MySQLPacket> {
+public final class MySQLComStmtCloseExecutor implements CommandExecutor {
     
     private final MySQLComStmtClosePacket packet;
     
     @Override
-    public Collection<MySQLPacket> execute() {
+    public Collection<DatabasePacket> execute() {
         packet.removeCachedStatement();
         return Collections.emptyList();
     }

sharding-proxy/sharding-proxy-frontend/sharding-proxy-frontend-mysql/src/main/java/org/apache/shardingsphere/shardingproxy/frontend/mysql/executor/query/binary/execute/MySQLQueryComStmtExecuteExecutor.java

@@ -29,6 +29,7 @@ import org.apache.shardingsphere.shardingproxy.backend.response.update.UpdateRes
 import org.apache.shardingsphere.shardingproxy.context.GlobalContext;
 import org.apache.shardingsphere.shardingproxy.error.CommonErrorCode;
 import org.apache.shardingsphere.shardingproxy.frontend.api.QueryCommandExecutor;
+import org.apache.shardingsphere.shardingproxy.transport.api.packet.DatabasePacket;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.constant.MySQLColumnType;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.MySQLPacket;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.command.query.MySQLColumnDefinition41Packet;
@@ -53,7 +54,7 @@ import java.util.List;
  * @author zhangyonglun
  * @author zhangliang
  */
-public final class MySQLQueryComStmtExecuteExecutor implements QueryCommandExecutor<MySQLPacket> {
+public final class MySQLQueryComStmtExecuteExecutor implements QueryCommandExecutor {
     
     private final DatabaseCommunicationEngine databaseCommunicationEngine;
     
@@ -67,16 +68,16 @@ public final class MySQLQueryComStmtExecuteExecutor implements QueryCommandExecu
     }
     
     @Override
-    public Collection<MySQLPacket> execute() {
+    public Collection<DatabasePacket> execute() {
         if (GlobalContext.getInstance().isCircuitBreak()) {
-            return Collections.<MySQLPacket>singletonList(new MySQLErrPacket(1, CommonErrorCode.CIRCUIT_BREAK_MODE));
+            return Collections.<DatabasePacket>singletonList(new MySQLErrPacket(1, CommonErrorCode.CIRCUIT_BREAK_MODE));
         }
         BackendResponse backendResponse = databaseCommunicationEngine.execute();
         if (backendResponse instanceof ErrorResponse) {
-            return Collections.<MySQLPacket>singletonList(createErrorPacket(((ErrorResponse) backendResponse).getCause()));
+            return Collections.<DatabasePacket>singletonList(createErrorPacket(((ErrorResponse) backendResponse).getCause()));
         }
         if (backendResponse instanceof UpdateResponse) {
-            return Collections.<MySQLPacket>singletonList(createUpdatePacket((UpdateResponse) backendResponse));
+            return Collections.<DatabasePacket>singletonList(createUpdatePacket((UpdateResponse) backendResponse));
         }
         isQuery = true;
         return createQueryPacket((QueryResponse) backendResponse);
@@ -90,8 +91,8 @@ public final class MySQLQueryComStmtExecuteExecutor implements QueryCommandExecu
         return new MySQLOKPacket(1, updateResponse.getUpdateCount(), updateResponse.getLastInsertId());
     }
     
-    private Collection<MySQLPacket> createQueryPacket(final QueryResponse backendResponse) {
-        Collection<MySQLPacket> result = new LinkedList<>();
+    private Collection<DatabasePacket> createQueryPacket(final QueryResponse backendResponse) {
+        Collection<DatabasePacket> result = new LinkedList<>();
         List<QueryHeader> queryHeader = backendResponse.getQueryHeaders();
         result.add(new MySQLFieldCountPacket(++currentSequenceId, queryHeader.size()));
         for (QueryHeader each : queryHeader) {

sharding-proxy/sharding-proxy-frontend/sharding-proxy-frontend-mysql/src/main/java/org/apache/shardingsphere/shardingproxy/frontend/mysql/executor/query/binary/prepare/MySQLComStmtPrepareExecutor.java

@@ -28,8 +28,8 @@ import org.apache.shardingsphere.shardingproxy.backend.schema.LogicSchemas;
 import org.apache.shardingsphere.shardingproxy.backend.schema.MasterSlaveSchema;
 import org.apache.shardingsphere.shardingproxy.backend.schema.ShardingSchema;
 import org.apache.shardingsphere.shardingproxy.frontend.api.CommandExecutor;
+import org.apache.shardingsphere.shardingproxy.transport.api.packet.DatabasePacket;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.constant.MySQLColumnType;
-import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.MySQLPacket;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.command.query.MySQLColumnDefinition41Packet;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.command.query.binary.MySQLBinaryStatementRegistry;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.command.query.binary.prepare.MySQLComStmtPrepareOKPacket;
@@ -45,7 +45,7 @@ import java.util.LinkedList;
  * @author zhangyonglun
  * @author zhangliang
  */
-public final class MySQLComStmtPrepareExecutor implements CommandExecutor<MySQLPacket> {
+public final class MySQLComStmtPrepareExecutor implements CommandExecutor {
     
     private static final MySQLBinaryStatementRegistry PREPARED_STATEMENT_REGISTRY = MySQLBinaryStatementRegistry.getInstance();
     
@@ -62,11 +62,11 @@ public final class MySQLComStmtPrepareExecutor implements CommandExecutor<MySQLP
     }
     
     @Override
-    public Collection<MySQLPacket> execute() {
+    public Collection<DatabasePacket> execute() {
         // TODO we should use none-sharding parsing engine in future.
         SQLParsingEngine sqlParsingEngine = new SQLParsingEngine(
                 LogicSchemas.getInstance().getDatabaseType(), packet.getSql(), getShardingRule(logicSchema), logicSchema.getMetaData().getTable());
-        Collection<MySQLPacket> result = new LinkedList<>();
+        Collection<DatabasePacket> result = new LinkedList<>();
         int currentSequenceId = 0;
         SQLStatement sqlStatement = sqlParsingEngine.parse(true);
         int parametersIndex = sqlStatement.getParametersIndex();

sharding-proxy/sharding-proxy-frontend/sharding-proxy-frontend-mysql/src/main/java/org/apache/shardingsphere/shardingproxy/frontend/mysql/executor/query/text/fieldlist/MySQLComFieldListPacketExecutor.java

@@ -23,8 +23,8 @@ import org.apache.shardingsphere.shardingproxy.backend.communication.jdbc.connec
 import org.apache.shardingsphere.shardingproxy.backend.response.BackendResponse;
 import org.apache.shardingsphere.shardingproxy.backend.response.error.ErrorResponse;
 import org.apache.shardingsphere.shardingproxy.frontend.api.CommandExecutor;
+import org.apache.shardingsphere.shardingproxy.transport.api.packet.DatabasePacket;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.constant.MySQLColumnType;
-import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.MySQLPacket;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.command.query.MySQLColumnDefinition41Packet;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.command.query.text.fieldlist.MySQLComFieldListPacket;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.generic.MySQLEofPacket;
@@ -40,7 +40,7 @@ import java.util.LinkedList;
  *
  * @author zhangliang 
  */
-public final class MySQLComFieldListPacketExecutor implements CommandExecutor<MySQLPacket> {
+public final class MySQLComFieldListPacketExecutor implements CommandExecutor {
     
     private static final String SQL = "SHOW COLUMNS FROM %s FROM %s";
     
@@ -57,9 +57,9 @@ public final class MySQLComFieldListPacketExecutor implements CommandExecutor<My
     }
     
     @Override
-    public Collection<MySQLPacket> execute() throws SQLException {
+    public Collection<DatabasePacket> execute() throws SQLException {
         BackendResponse backendResponse = databaseCommunicationEngine.execute();
-        return backendResponse instanceof ErrorResponse ? Collections.<MySQLPacket>singletonList(MySQLErrPacketFactory.newInstance(1, ((ErrorResponse) backendResponse).getCause())) 
+        return backendResponse instanceof ErrorResponse ? Collections.<DatabasePacket>singletonList(MySQLErrPacketFactory.newInstance(1, ((ErrorResponse) backendResponse).getCause())) 
                 : getColumnDefinition41Packets();
     }
     
@@ -67,8 +67,8 @@ public final class MySQLComFieldListPacketExecutor implements CommandExecutor<My
         return String.format(SQL, packet.getTable(), schemaName);
     }
     
-    private Collection<MySQLPacket> getColumnDefinition41Packets() throws SQLException {
-        Collection<MySQLPacket> result = new LinkedList<>();
+    private Collection<DatabasePacket> getColumnDefinition41Packets() throws SQLException {
+        Collection<DatabasePacket> result = new LinkedList<>();
         int currentSequenceId = 0;
         while (databaseCommunicationEngine.next()) {
             String columnName = databaseCommunicationEngine.getQueryData().getData().get(0).toString();

sharding-proxy/sharding-proxy-frontend/sharding-proxy-frontend-mysql/src/main/java/org/apache/shardingsphere/shardingproxy/frontend/mysql/executor/query/text/query/MySQLComQueryPacketExecutor.java

@@ -28,6 +28,7 @@ import org.apache.shardingsphere.shardingproxy.backend.text.TextProtocolBackendH
 import org.apache.shardingsphere.shardingproxy.context.GlobalContext;
 import org.apache.shardingsphere.shardingproxy.error.CommonErrorCode;
 import org.apache.shardingsphere.shardingproxy.frontend.api.QueryCommandExecutor;
+import org.apache.shardingsphere.shardingproxy.transport.api.packet.DatabasePacket;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.MySQLPacket;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.command.query.MySQLColumnDefinition41Packet;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.packet.command.query.MySQLFieldCountPacket;
@@ -49,7 +50,7 @@ import java.util.List;
  *
  * @author zhangliang
  */
-public final class MySQLComQueryPacketExecutor implements QueryCommandExecutor<MySQLPacket> {
+public final class MySQLComQueryPacketExecutor implements QueryCommandExecutor {
     
     private final TextProtocolBackendHandler textProtocolBackendHandler;
     
@@ -62,16 +63,16 @@ public final class MySQLComQueryPacketExecutor implements QueryCommandExecutor<M
     }
     
     @Override
-    public Collection<MySQLPacket> execute() {
+    public Collection<DatabasePacket> execute() {
         if (GlobalContext.getInstance().isCircuitBreak()) {
-            return Collections.<MySQLPacket>singletonList(new MySQLErrPacket(1, CommonErrorCode.CIRCUIT_BREAK_MODE));
+            return Collections.<DatabasePacket>singletonList(new MySQLErrPacket(1, CommonErrorCode.CIRCUIT_BREAK_MODE));
         }
         BackendResponse backendResponse = textProtocolBackendHandler.execute();
         if (backendResponse instanceof ErrorResponse) {
-            return Collections.<MySQLPacket>singletonList(createErrorPacket(((ErrorResponse) backendResponse).getCause()));
+            return Collections.<DatabasePacket>singletonList(createErrorPacket(((ErrorResponse) backendResponse).getCause()));
         }
         if (backendResponse instanceof UpdateResponse) {
-            return Collections.<MySQLPacket>singletonList(createUpdatePacket((UpdateResponse) backendResponse));
+            return Collections.<DatabasePacket>singletonList(createUpdatePacket((UpdateResponse) backendResponse));
         }
         isQuery = true;
         return createQueryPackets((QueryResponse) backendResponse);
@@ -85,8 +86,8 @@ public final class MySQLComQueryPacketExecutor implements QueryCommandExecutor<M
         return new MySQLOKPacket(1, updateResponse.getUpdateCount(), updateResponse.getLastInsertId());
     }
     
-    private Collection<MySQLPacket> createQueryPackets(final QueryResponse backendResponse) {
-        Collection<MySQLPacket> result = new LinkedList<>();
+    private Collection<DatabasePacket> createQueryPackets(final QueryResponse backendResponse) {
+        Collection<DatabasePacket> result = new LinkedList<>();
         List<QueryHeader> queryHeader = backendResponse.getQueryHeaders();
         result.add(new MySQLFieldCountPacket(++currentSequenceId, queryHeader.size()));
         for (QueryHeader each : queryHeader) {

sharding-proxy/sharding-proxy-frontend/sharding-proxy-frontend-postgresql/src/main/java/org/apache/shardingsphere/shardingproxy/frontend/postgresql/PostgreSQLFrontendEngine.java

@@ -35,7 +35,6 @@ import org.apache.shardingsphere.shardingproxy.transport.api.packet.CommandPacke
 import org.apache.shardingsphere.shardingproxy.transport.api.packet.CommandPacketType;
 import org.apache.shardingsphere.shardingproxy.transport.api.packet.DatabasePacket;
 import org.apache.shardingsphere.shardingproxy.transport.api.payload.PacketPayload;
-import org.apache.shardingsphere.shardingproxy.transport.postgresql.packet.PostgreSQLPacket;
 import org.apache.shardingsphere.shardingproxy.transport.postgresql.packet.command.PostgreSQLCommandPacket;
 import org.apache.shardingsphere.shardingproxy.transport.postgresql.packet.command.PostgreSQLCommandPacketFactory;
 import org.apache.shardingsphere.shardingproxy.transport.postgresql.packet.command.PostgreSQLCommandPacketType;
@@ -129,7 +128,7 @@ public final class PostgreSQLFrontendEngine implements DatabaseFrontendEngine {
     }
     
     @Override
-    public CommandExecutor<PostgreSQLPacket> getCommandExecutor(final CommandPacketType type, final CommandPacket packet, final BackendConnection backendConnection) {
+    public CommandExecutor getCommandExecutor(final CommandPacketType type, final CommandPacket packet, final BackendConnection backendConnection) {
         return PostgreSQLCommandExecutorFactory.newInstance((PostgreSQLCommandPacketType) type, (PostgreSQLCommandPacket) packet, backendConnection);
     }
     
@@ -148,10 +147,10 @@ public final class PostgreSQLFrontendEngine implements DatabaseFrontendEngine {
     }
     
     private void writePackets(final ChannelHandlerContext context, final PostgreSQLPacketPayload payload, final BackendConnection backendConnection) throws SQLException {
-        PostgreSQLCommandPacketType type = getCommandPacketType(payload);
-        PostgreSQLCommandPacket commandPacket = getCommandPacket(payload, type, backendConnection);
-        CommandExecutor<PostgreSQLPacket> commandExecutor = getCommandExecutor(type, commandPacket, backendConnection);
-        Collection<PostgreSQLPacket> responsePackets = commandExecutor.execute();
+        CommandPacketType type = getCommandPacketType(payload);
+        CommandPacket commandPacket = getCommandPacket(payload, type, backendConnection);
+        CommandExecutor commandExecutor = getCommandExecutor(type, commandPacket, backendConnection);
+        Collection<DatabasePacket> responsePackets = commandExecutor.execute();
         if (commandPacket instanceof PostgreSQLComSyncPacket) {
             context.write(new PostgreSQLCommandCompletePacket());
             context.writeAndFlush(new PostgreSQLReadyForQueryPacket());
@@ -160,11 +159,11 @@ public final class PostgreSQLFrontendEngine implements DatabaseFrontendEngine {
         if (responsePackets.isEmpty()) {
             return;
         }
-        for (PostgreSQLPacket each : responsePackets) {
+        for (DatabasePacket each : responsePackets) {
             context.write(each);
         }
         if (commandExecutor instanceof QueryCommandExecutor) {
-            writeQueryData(context, backendConnection, (QueryCommandExecutor<PostgreSQLPacket>) commandExecutor, 0);
+            writeQueryData(context, backendConnection, (QueryCommandExecutor) commandExecutor, responsePackets.size());
         }
         if (commandPacket instanceof PostgreSQLComQueryPacket) {
             context.write(new PostgreSQLCommandCompletePacket());
@@ -174,7 +173,7 @@ public final class PostgreSQLFrontendEngine implements DatabaseFrontendEngine {
     
     @Override
     public void writeQueryData(final ChannelHandlerContext context,
-                               final BackendConnection backendConnection, final QueryCommandExecutor<?> queryCommandExecutor, final int sequenceIdOffset) throws SQLException {
+                               final BackendConnection backendConnection, final QueryCommandExecutor queryCommandExecutor, final int headerPackagesCount) throws SQLException {
         if (queryCommandExecutor.isQuery() && !context.channel().isActive()) {
             return;
         }

sharding-proxy/sharding-proxy-frontend/sharding-proxy-frontend-postgresql/src/main/java/org/apache/shardingsphere/shardingproxy/frontend/postgresql/executor/PostgreSQLCommandExecutorFactory.java

@@ -29,7 +29,6 @@ import org.apache.shardingsphere.shardingproxy.frontend.postgresql.executor.quer
 import org.apache.shardingsphere.shardingproxy.frontend.postgresql.executor.query.binary.parse.PostgreSQLComParseExecutor;
 import org.apache.shardingsphere.shardingproxy.frontend.postgresql.executor.query.binary.sync.PostgreSQLComSyncExecutor;
 import org.apache.shardingsphere.shardingproxy.frontend.postgresql.executor.query.text.PostgreSQLComQueryExecutor;
-import org.apache.shardingsphere.shardingproxy.transport.postgresql.packet.PostgreSQLPacket;
 import org.apache.shardingsphere.shardingproxy.transport.postgresql.packet.command.PostgreSQLCommandPacket;
 import org.apache.shardingsphere.shardingproxy.transport.postgresql.packet.command.PostgreSQLCommandPacketType;
 import org.apache.shardingsphere.shardingproxy.transport.postgresql.packet.command.query.binary.bind.PostgreSQLComBindPacket;
@@ -52,8 +51,7 @@ public final class PostgreSQLCommandExecutorFactory {
      * @param backendConnection backend connection
      * @return command executor
      */
-    public static CommandExecutor<PostgreSQLPacket> newInstance(
-            final PostgreSQLCommandPacketType commandPacketType, final PostgreSQLCommandPacket commandPacket, final BackendConnection backendConnection) {
+    public static CommandExecutor newInstance(final PostgreSQLCommandPacketType commandPacketType, final PostgreSQLCommandPacket commandPacket, final BackendConnection backendConnection) {
         switch (commandPacketType) {
             case QUERY:
                 return new PostgreSQLComQueryExecutor((PostgreSQLComQueryPacket) commandPacket, backendConnection);

sharding-proxy/sharding-proxy-frontend/sharding-proxy-frontend-postgresql/src/main/java/org/apache/shardingsphere/shardingproxy/frontend/postgresql/executor/generic/PostgreSQLComTerminationExecutor.java

@@ -18,7 +18,7 @@
 package org.apache.shardingsphere.shardingproxy.frontend.postgresql.executor.generic;
 
 import org.apache.shardingsphere.shardingproxy.frontend.api.CommandExecutor;
-import org.apache.shardingsphere.shardingproxy.transport.postgresql.packet.PostgreSQLPacket;
+import org.apache.shardingsphere.shardingproxy.transport.api.packet.DatabasePacket;
 
 import java.util.Collection;
 import java.util.Collections;
@@ -28,10 +28,10 @@ import java.util.Collections;
  * 
  * @author zhangliang
  */
-public final class PostgreSQLComTerminationExecutor implements CommandExecutor<PostgreSQLPacket> {
+public final class PostgreSQLComTerminationExecutor implements CommandExecutor {
     
     @Override
-    public Collection<PostgreSQLPacket> execute() {
+    public Collection<DatabasePacket> execute() {
         return Collections.emptyList();
     }
 }

sharding-proxy/sharding-proxy-frontend/sharding-proxy-frontend-postgresql/src/main/java/org/apache/shardingsphere/shardingproxy/frontend/postgresql/executor/generic/PostgreSQLUnsupportedCommandExecutor.java

@@ -18,7 +18,7 @@
 package org.apache.shardingsphere.shardingproxy.frontend.postgresql.executor.generic;
 
 import org.apache.shardingsphere.shardingproxy.frontend.api.CommandExecutor;
-import org.apache.shardingsphere.shardingproxy.transport.postgresql.packet.PostgreSQLPacket;
+import org.apache.shardingsphere.shardingproxy.transport.api.packet.DatabasePacket;
 import org.apache.shardingsphere.shardingproxy.transport.postgresql.packet.generic.PostgreSQLErrorResponsePacket;
 
 import java.util.Collection;
@@ -30,10 +30,10 @@ import java.util.Collections;
  * @author zhangyonglun
  * @author zhangliang
  */
-public final class PostgreSQLUnsupportedCommandExecutor implements CommandExecutor<PostgreSQLPacket> {
+public final class PostgreSQLUnsupportedCommandExecutor implements CommandExecutor {
     
     @Override
-    public Collection<PostgreSQLPacket> execute() {
-        return Collections.<PostgreSQLPacket>singletonList(new PostgreSQLErrorResponsePacket());
+    public Collection<DatabasePacket> execute() {
+        return Collections.<DatabasePacket>singletonList(new PostgreSQLErrorResponsePacket());
     }
 }

sharding-proxy/sharding-proxy-frontend/sharding-proxy-frontend-postgresql/src/main/java/org/apache/shardingsphere/shardingproxy/frontend/postgresql/executor/query/binary/bind/PostgreSQLComBindExecutor.java

@@ -29,6 +29,7 @@ import org.apache.shardingsphere.shardingproxy.backend.response.query.QueryRespo
 import org.apache.shardingsphere.shardingproxy.backend.response.update.UpdateResponse;
 import org.apache.shardingsphere.shardingproxy.context.GlobalContext;
 import org.apache.shardingsphere.shardingproxy.frontend.api.QueryCommandExecutor;
+import org.apache.shardingsphere.shardingproxy.transport.api.packet.DatabasePacket;
 import org.apache.shardingsphere.shardingproxy.transport.postgresql.constant.PostgreSQLColumnType;
 import org.apache.shardingsphere.shardingproxy.transport.postgresql.packet.PostgreSQLPacket;
 import org.apache.shardingsphere.shardingproxy.transport.postgresql.packet.command.query.PostgreSQLColumnDescription;
@@ -53,7 +54,7 @@ import java.util.List;
  * @author zhangyonglun
  * @author zhangliang
  */
-public final class PostgreSQLComBindExecutor implements QueryCommandExecutor<PostgreSQLPacket> {
+public final class PostgreSQLComBindExecutor implements QueryCommandExecutor {
     
     private final PostgreSQLComBindPacket packet;
             
@@ -68,11 +69,11 @@ public final class PostgreSQLComBindExecutor implements QueryCommandExecutor<Pos
     }
     
     @Override
-    public Collection<PostgreSQLPacket> execute() {
+    public Collection<DatabasePacket> execute() {
         if (GlobalContext.getInstance().isCircuitBreak()) {
-            return Collections.<PostgreSQLPacket>singletonList(new PostgreSQLErrorResponsePacket());
+            return Collections.<DatabasePacket>singletonList(new PostgreSQLErrorResponsePacket());
         }
-        List<PostgreSQLPacket> result = new LinkedList<>();
+        List<DatabasePacket> result = new LinkedList<>();
         result.add(new PostgreSQLBindCompletePacket());
         if (null == databaseCommunicationEngine) {
             return result;

sharding-proxy/sharding-proxy-frontend/sharding-proxy-frontend-postgresql/src/main/java/org/apache/shardingsphere/shardingproxy/frontend/postgresql/executor/query/binary/describe/PostgreSQLComDescribeExecutor.java

@@ -18,7 +18,7 @@
 package org.apache.shardingsphere.shardingproxy.frontend.postgresql.executor.query.binary.describe;
 
 import org.apache.shardingsphere.shardingproxy.frontend.api.CommandExecutor;
-import org.apache.shardingsphere.shardingproxy.transport.postgresql.packet.PostgreSQLPacket;
+import org.apache.shardingsphere.shardingproxy.transport.api.packet.DatabasePacket;
 
 import java.util.Collection;
 import java.util.Collections;
@@ -29,10 +29,10 @@ import java.util.Collections;
  * @author zhangyonglun
  * @author zhangliang
  */
-public final class PostgreSQLComDescribeExecutor implements CommandExecutor<PostgreSQLPacket> {
+public final class PostgreSQLComDescribeExecutor implements CommandExecutor {
     
     @Override
-    public Collection<PostgreSQLPacket> execute() {
+    public Collection<DatabasePacket> execute() {
         return Collections.emptyList();
     }
 }

sharding-proxy/sharding-proxy-frontend/sharding-proxy-frontend-postgresql/src/main/java/org/apache/shardingsphere/shardingproxy/frontend/postgresql/executor/query/binary/execute/PostgreSQLComExecuteExecutor.java

@@ -18,7 +18,7 @@
 package org.apache.shardingsphere.shardingproxy.frontend.postgresql.executor.query.binary.execute;
 
 import org.apache.shardingsphere.shardingproxy.frontend.api.CommandExecutor;
-import org.apache.shardingsphere.shardingproxy.transport.postgresql.packet.PostgreSQLPacket;
+import org.apache.shardingsphere.shardingproxy.transport.api.packet.DatabasePacket;
 
 import java.util.Collection;
 import java.util.Collections;
@@ -29,10 +29,10 @@ import java.util.Collections;
  * @author zhangyonglun
  * @author zhangliang
  */
-public final class PostgreSQLComExecuteExecutor implements CommandExecutor<PostgreSQLPacket> {
+public final class PostgreSQLComExecuteExecutor implements CommandExecutor {
     
     @Override
-    public Collection<PostgreSQLPacket> execute() {
+    public Collection<DatabasePacket> execute() {
         return Collections.emptyList();
     }
 }

sharding-proxy/sharding-proxy-frontend/sharding-proxy-frontend-postgresql/src/main/java/org/apache/shardingsphere/shardingproxy/frontend/postgresql/executor/query/binary/parse/PostgreSQLComParseExecutor.java

@@ -26,7 +26,7 @@ import org.apache.shardingsphere.shardingproxy.backend.schema.LogicSchema;
 import org.apache.shardingsphere.shardingproxy.backend.schema.MasterSlaveSchema;
 import org.apache.shardingsphere.shardingproxy.backend.schema.ShardingSchema;
 import org.apache.shardingsphere.shardingproxy.frontend.api.CommandExecutor;
-import org.apache.shardingsphere.shardingproxy.transport.postgresql.packet.PostgreSQLPacket;
+import org.apache.shardingsphere.shardingproxy.transport.api.packet.DatabasePacket;
 import org.apache.shardingsphere.shardingproxy.transport.postgresql.packet.command.query.binary.BinaryStatementRegistry;
 import org.apache.shardingsphere.shardingproxy.transport.postgresql.packet.command.query.binary.ConnectionScopeBinaryStatementRegistry;
 import org.apache.shardingsphere.shardingproxy.transport.postgresql.packet.command.query.binary.parse.PostgreSQLComParsePacket;
@@ -41,7 +41,7 @@ import java.util.Collections;
  * @author zhangyonglun
  * @author zhangliang
  */
-public final class PostgreSQLComParseExecutor implements CommandExecutor<PostgreSQLPacket> {
+public final class PostgreSQLComParseExecutor implements CommandExecutor {
     
     private final PostgreSQLComParsePacket packet;
     
@@ -56,7 +56,7 @@ public final class PostgreSQLComParseExecutor implements CommandExecutor<Postgre
     }
     
     @Override
-    public Collection<PostgreSQLPacket> execute() {
+    public Collection<DatabasePacket> execute() {
         // TODO we should use none-sharding parsing engine in future.
         SQLParsingEngine sqlParsingEngine = new SQLParsingEngine(DatabaseType.PostgreSQL, packet.getSql(), getShardingRule(logicSchema), logicSchema.getMetaData().getTable());
         if (!packet.getSql().isEmpty()) {
@@ -64,7 +64,7 @@ public final class PostgreSQLComParseExecutor implements CommandExecutor<Postgre
             int parametersIndex = sqlStatement.getParametersIndex();
             binaryStatementRegistry.register(packet.getStatementId(), packet.getSql(), parametersIndex, packet.getBinaryStatementParameterTypes());
         }
-        return Collections.<PostgreSQLPacket>singletonList(new PostgreSQLParseCompletePacket());
+        return Collections.<DatabasePacket>singletonList(new PostgreSQLParseCompletePacket());
     }
     
     private ShardingRule getShardingRule(final LogicSchema logicSchema) {

sharding-proxy/sharding-proxy-frontend/sharding-proxy-frontend-postgresql/src/main/java/org/apache/shardingsphere/shardingproxy/frontend/postgresql/executor/query/binary/sync/PostgreSQLComSyncExecutor.java

@@ -18,7 +18,7 @@
 package org.apache.shardingsphere.shardingproxy.frontend.postgresql.executor.query.binary.sync;
 
 import org.apache.shardingsphere.shardingproxy.frontend.api.CommandExecutor;
-import org.apache.shardingsphere.shardingproxy.transport.postgresql.packet.PostgreSQLPacket;
+import org.apache.shardingsphere.shardingproxy.transport.api.packet.DatabasePacket;
 
 import java.util.Collection;
 import java.util.Collections;
@@ -29,10 +29,10 @@ import java.util.Collections;
  * @author zhangyonglun
  * @author zhangliang
  */
-public final class PostgreSQLComSyncExecutor implements CommandExecutor<PostgreSQLPacket> {
+public final class PostgreSQLComSyncExecutor implements CommandExecutor {
     
     @Override
-    public Collection<PostgreSQLPacket> execute() {
+    public Collection<DatabasePacket> execute() {
         return Collections.emptyList();
     }
 }

sharding-proxy/sharding-proxy-frontend/sharding-proxy-frontend-postgresql/src/main/java/org/apache/shardingsphere/shardingproxy/frontend/postgresql/executor/query/text/PostgreSQLComQueryExecutor.java

@@ -28,6 +28,7 @@ import org.apache.shardingsphere.shardingproxy.backend.text.TextProtocolBackendH
 import org.apache.shardingsphere.shardingproxy.backend.text.TextProtocolBackendHandlerFactory;
 import org.apache.shardingsphere.shardingproxy.context.GlobalContext;
 import org.apache.shardingsphere.shardingproxy.frontend.api.QueryCommandExecutor;
+import org.apache.shardingsphere.shardingproxy.transport.api.packet.DatabasePacket;
 import org.apache.shardingsphere.shardingproxy.transport.postgresql.packet.PostgreSQLPacket;
 import org.apache.shardingsphere.shardingproxy.transport.postgresql.packet.command.query.PostgreSQLColumnDescription;
 import org.apache.shardingsphere.shardingproxy.transport.postgresql.packet.command.query.PostgreSQLRowDescriptionPacket;
@@ -48,7 +49,7 @@ import java.util.List;
  * @author zhangyonglun
  * @author zhangliang
  */
-public final class PostgreSQLComQueryExecutor implements QueryCommandExecutor<PostgreSQLPacket> {
+public final class PostgreSQLComQueryExecutor implements QueryCommandExecutor {
     
     private final TextProtocolBackendHandler textProtocolBackendHandler;
     
@@ -59,19 +60,19 @@ public final class PostgreSQLComQueryExecutor implements QueryCommandExecutor<Po
     }
     
     @Override
-    public Collection<PostgreSQLPacket> execute() {
+    public Collection<DatabasePacket> execute() {
         if (GlobalContext.getInstance().isCircuitBreak()) {
-            return Collections.<PostgreSQLPacket>singletonList(new PostgreSQLErrorResponsePacket());
+            return Collections.<DatabasePacket>singletonList(new PostgreSQLErrorResponsePacket());
         }
         BackendResponse backendResponse = textProtocolBackendHandler.execute();
         if (backendResponse instanceof ErrorResponse) {
-            return Collections.<PostgreSQLPacket>singletonList(createErrorPacket((ErrorResponse) backendResponse));
+            return Collections.<DatabasePacket>singletonList(createErrorPacket((ErrorResponse) backendResponse));
         }
         if (backendResponse instanceof UpdateResponse) {
-            return Collections.<PostgreSQLPacket>singletonList(createUpdatePacket((UpdateResponse) backendResponse));
+            return Collections.<DatabasePacket>singletonList(createUpdatePacket((UpdateResponse) backendResponse));
         }
         Optional<PostgreSQLRowDescriptionPacket> result = createQueryPacket((QueryResponse) backendResponse);
-        return result.isPresent() ? Collections.<PostgreSQLPacket>singletonList(result.get()) : Collections.<PostgreSQLPacket>emptyList();
+        return result.isPresent() ? Collections.<DatabasePacket>singletonList(result.get()) : Collections.<DatabasePacket>emptyList();
     }
     
     private PostgreSQLErrorResponsePacket createErrorPacket(final ErrorResponse errorResponse) {

sharding-proxy/sharding-proxy-frontend/sharding-proxy-frontend-spi/src/main/java/org/apache/shardingsphere/shardingproxy/frontend/api/CommandExecutor.java

@@ -26,10 +26,8 @@ import java.util.Collection;
  * Command executor.
  *
  * @author zhangliang
- * 
- * @param <T> type of database packet
  */
-public interface CommandExecutor<T extends DatabasePacket> {
+public interface CommandExecutor {
     
     /**
      * Execute command.
@@ -37,5 +35,5 @@ public interface CommandExecutor<T extends DatabasePacket> {
      * @return database packets to be sent
      * @throws SQLException SQL exception
      */
-    Collection<T> execute() throws SQLException;
+    Collection<DatabasePacket> execute() throws SQLException;
 }

sharding-proxy/sharding-proxy-frontend/sharding-proxy-frontend-spi/src/main/java/org/apache/shardingsphere/shardingproxy/frontend/api/QueryCommandExecutor.java

@@ -25,10 +25,8 @@ import java.sql.SQLException;
  * Query command executor.
  *
  * @author zhangliang
- * 
- * @param <T> type of database packet
  */
-public interface QueryCommandExecutor<T extends DatabasePacket> extends CommandExecutor<T> {
+public interface QueryCommandExecutor extends CommandExecutor {
     
     /**
      * Judge is query SQL or not.
@@ -51,5 +49,5 @@ public interface QueryCommandExecutor<T extends DatabasePacket> extends CommandE
      * @return database packet of query data
      * @throws SQLException SQL exception
      */
-    T getQueryData() throws SQLException;
+    DatabasePacket getQueryData() throws SQLException;
 }

sharding-proxy/sharding-proxy-frontend/sharding-proxy-frontend-spi/src/main/java/org/apache/shardingsphere/shardingproxy/frontend/spi/DatabaseFrontendEngine.java

@@ -115,13 +115,14 @@ public interface DatabaseFrontendEngine {
     
     /**
      * Write query data.
+     * 
      * @param context channel handler context
      * @param backendConnection backend connection
      * @param queryCommandExecutor query command executor
-     * @param sequenceIdOffset sequence ID offset
+     * @param headerPackagesCount count of header packages
      * @throws SQLException SQL exception
      */
-    void writeQueryData(ChannelHandlerContext context, BackendConnection backendConnection, QueryCommandExecutor<?> queryCommandExecutor, int sequenceIdOffset) throws SQLException;
+    void writeQueryData(ChannelHandlerContext context, BackendConnection backendConnection, QueryCommandExecutor queryCommandExecutor, int headerPackagesCount) throws SQLException;
     
     /**
      * Release resource.