diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 724888a7..831187a6 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -52,10 +52,10 @@ export PATH=$PATH:$GOBIN
 export DEST_DIR=$GOPATH/src
 
 export SRC_DIR=$GOPATH/src/github.com/rqlite/rqlite/command
-protoc -I=$SRC_DIR --go_out=$DEST_DIR $SRC_DIR/command.proto
+protoc -I=$SRC_DIR --proto_path=$GOPATHsrc/github.com/rqlite/rqlite --go_out=$DEST_DIR $SRC_DIR/command.proto
 
 export SRC_DIR=$GOPATH/src/github.com/rqlite/rqlite/cluster
-protoc -I=$SRC_DIR --go_out=$DEST_DIR $SRC_DIR/message.proto
+protoc -I=$SRC_DIR --proto_path=$GOPATHsrc/github.com/rqlite/rqlite --go_out=$DEST_DIR $SRC_DIR/message.proto
 ```
 
 ### Speeding up the build process
diff --git a/cluster/message.pb.go b/cluster/message.pb.go
index ecb1d42b..4c1c255b 100644
--- a/cluster/message.pb.go
+++ b/cluster/message.pb.go
@@ -1,12 +1,13 @@
 // Code generated by protoc-gen-go. DO NOT EDIT.
 // versions:
-// 	protoc-gen-go v1.26.0
+// 	protoc-gen-go v1.27.1
 // 	protoc        v3.13.0
 // source: message.proto
 
 package cluster
 
 import (
+	command "github.com/rqlite/rqlite/command"
 	protoreflect "google.golang.org/protobuf/reflect/protoreflect"
 	protoimpl "google.golang.org/protobuf/runtime/protoimpl"
 	reflect "reflect"
@@ -25,6 +26,8 @@ type Command_Type int32
 const (
 	Command_COMMAND_TYPE_UNKNOWN          Command_Type = 0
 	Command_COMMAND_TYPE_GET_NODE_API_URL Command_Type = 1
+	Command_COMMAND_TYPE_EXECUTE          Command_Type = 2
+	Command_COMMAND_TYPE_QUERY            Command_Type = 3
 )
 
 // Enum value maps for Command_Type.
@@ -32,10 +35,14 @@ var (
 	Command_Type_name = map[int32]string{
 		0: "COMMAND_TYPE_UNKNOWN",
 		1: "COMMAND_TYPE_GET_NODE_API_URL",
+		2: "COMMAND_TYPE_EXECUTE",
+		3: "COMMAND_TYPE_QUERY",
 	}
 	Command_Type_value = map[string]int32{
 		"COMMAND_TYPE_UNKNOWN":          0,
 		"COMMAND_TYPE_GET_NODE_API_URL": 1,
+		"COMMAND_TYPE_EXECUTE":          2,
+		"COMMAND_TYPE_QUERY":            3,
 	}
 )
 
@@ -118,7 +125,8 @@ type Command struct {
 	sizeCache     protoimpl.SizeCache
 	unknownFields protoimpl.UnknownFields
 
-	Type Command_Type `protobuf:"varint,1,opt,name=type,proto3,enum=Command_Type" json:"type,omitempty"`
+	Type       Command_Type `protobuf:"varint,1,opt,name=type,proto3,enum=cluster.Command_Type" json:"type,omitempty"`
+	SubCommand []byte       `protobuf:"bytes,2,opt,name=sub_command,json=subCommand,proto3" json:"sub_command,omitempty"`
 }
 
 func (x *Command) Reset() {
@@ -160,22 +168,158 @@ func (x *Command) GetType() Command_Type {
 	return Command_COMMAND_TYPE_UNKNOWN
 }
 
+func (x *Command) GetSubCommand() []byte {
+	if x != nil {
+		return x.SubCommand
+	}
+	return nil
+}
+
+type CommandExecuteResponse struct {
+	state         protoimpl.MessageState
+	sizeCache     protoimpl.SizeCache
+	unknownFields protoimpl.UnknownFields
+
+	Error   string                   `protobuf:"bytes,1,opt,name=error,proto3" json:"error,omitempty"`
+	Results []*command.ExecuteResult `protobuf:"bytes,2,rep,name=results,proto3" json:"results,omitempty"`
+}
+
+func (x *CommandExecuteResponse) Reset() {
+	*x = CommandExecuteResponse{}
+	if protoimpl.UnsafeEnabled {
+		mi := &file_message_proto_msgTypes[2]
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		ms.StoreMessageInfo(mi)
+	}
+}
+
+func (x *CommandExecuteResponse) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*CommandExecuteResponse) ProtoMessage() {}
+
+func (x *CommandExecuteResponse) ProtoReflect() protoreflect.Message {
+	mi := &file_message_proto_msgTypes[2]
+	if protoimpl.UnsafeEnabled && x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use CommandExecuteResponse.ProtoReflect.Descriptor instead.
+func (*CommandExecuteResponse) Descriptor() ([]byte, []int) {
+	return file_message_proto_rawDescGZIP(), []int{2}
+}
+
+func (x *CommandExecuteResponse) GetError() string {
+	if x != nil {
+		return x.Error
+	}
+	return ""
+}
+
+func (x *CommandExecuteResponse) GetResults() []*command.ExecuteResult {
+	if x != nil {
+		return x.Results
+	}
+	return nil
+}
+
+type CommandQueryResponse struct {
+	state         protoimpl.MessageState
+	sizeCache     protoimpl.SizeCache
+	unknownFields protoimpl.UnknownFields
+
+	Error string               `protobuf:"bytes,1,opt,name=error,proto3" json:"error,omitempty"`
+	Rows  []*command.QueryRows `protobuf:"bytes,2,rep,name=rows,proto3" json:"rows,omitempty"`
+}
+
+func (x *CommandQueryResponse) Reset() {
+	*x = CommandQueryResponse{}
+	if protoimpl.UnsafeEnabled {
+		mi := &file_message_proto_msgTypes[3]
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		ms.StoreMessageInfo(mi)
+	}
+}
+
+func (x *CommandQueryResponse) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*CommandQueryResponse) ProtoMessage() {}
+
+func (x *CommandQueryResponse) ProtoReflect() protoreflect.Message {
+	mi := &file_message_proto_msgTypes[3]
+	if protoimpl.UnsafeEnabled && x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use CommandQueryResponse.ProtoReflect.Descriptor instead.
+func (*CommandQueryResponse) Descriptor() ([]byte, []int) {
+	return file_message_proto_rawDescGZIP(), []int{3}
+}
+
+func (x *CommandQueryResponse) GetError() string {
+	if x != nil {
+		return x.Error
+	}
+	return ""
+}
+
+func (x *CommandQueryResponse) GetRows() []*command.QueryRows {
+	if x != nil {
+		return x.Rows
+	}
+	return nil
+}
+
 var File_message_proto protoreflect.FileDescriptor
 
 var file_message_proto_rawDesc = []byte{
-	0x0a, 0x0d, 0x6d, 0x65, 0x73, 0x73, 0x61, 0x67, 0x65, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x22,
+	0x0a, 0x0d, 0x6d, 0x65, 0x73, 0x73, 0x61, 0x67, 0x65, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x12,
+	0x07, 0x63, 0x6c, 0x75, 0x73, 0x74, 0x65, 0x72, 0x1a, 0x15, 0x63, 0x6f, 0x6d, 0x6d, 0x61, 0x6e,
+	0x64, 0x2f, 0x63, 0x6f, 0x6d, 0x6d, 0x61, 0x6e, 0x64, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x22,
 	0x1b, 0x0a, 0x07, 0x41, 0x64, 0x64, 0x72, 0x65, 0x73, 0x73, 0x12, 0x10, 0x0a, 0x03, 0x75, 0x72,
-	0x6c, 0x18, 0x01, 0x20, 0x01, 0x28, 0x09, 0x52, 0x03, 0x75, 0x72, 0x6c, 0x22, 0x71, 0x0a, 0x07,
-	0x43, 0x6f, 0x6d, 0x6d, 0x61, 0x6e, 0x64, 0x12, 0x21, 0x0a, 0x04, 0x74, 0x79, 0x70, 0x65, 0x18,
-	0x01, 0x20, 0x01, 0x28, 0x0e, 0x32, 0x0d, 0x2e, 0x43, 0x6f, 0x6d, 0x6d, 0x61, 0x6e, 0x64, 0x2e,
-	0x54, 0x79, 0x70, 0x65, 0x52, 0x04, 0x74, 0x79, 0x70, 0x65, 0x22, 0x43, 0x0a, 0x04, 0x54, 0x79,
-	0x70, 0x65, 0x12, 0x18, 0x0a, 0x14, 0x43, 0x4f, 0x4d, 0x4d, 0x41, 0x4e, 0x44, 0x5f, 0x54, 0x59,
-	0x50, 0x45, 0x5f, 0x55, 0x4e, 0x4b, 0x4e, 0x4f, 0x57, 0x4e, 0x10, 0x00, 0x12, 0x21, 0x0a, 0x1d,
-	0x43, 0x4f, 0x4d, 0x4d, 0x41, 0x4e, 0x44, 0x5f, 0x54, 0x59, 0x50, 0x45, 0x5f, 0x47, 0x45, 0x54,
-	0x5f, 0x4e, 0x4f, 0x44, 0x45, 0x5f, 0x41, 0x50, 0x49, 0x5f, 0x55, 0x52, 0x4c, 0x10, 0x01, 0x42,
-	0x22, 0x5a, 0x20, 0x67, 0x69, 0x74, 0x68, 0x75, 0x62, 0x2e, 0x63, 0x6f, 0x6d, 0x2f, 0x72, 0x71,
-	0x6c, 0x69, 0x74, 0x65, 0x2f, 0x72, 0x71, 0x6c, 0x69, 0x74, 0x65, 0x2f, 0x63, 0x6c, 0x75, 0x73,
-	0x74, 0x65, 0x72, 0x62, 0x06, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x33,
+	0x6c, 0x18, 0x01, 0x20, 0x01, 0x28, 0x09, 0x52, 0x03, 0x75, 0x72, 0x6c, 0x22, 0xcc, 0x01, 0x0a,
+	0x07, 0x43, 0x6f, 0x6d, 0x6d, 0x61, 0x6e, 0x64, 0x12, 0x29, 0x0a, 0x04, 0x74, 0x79, 0x70, 0x65,
+	0x18, 0x01, 0x20, 0x01, 0x28, 0x0e, 0x32, 0x15, 0x2e, 0x63, 0x6c, 0x75, 0x73, 0x74, 0x65, 0x72,
+	0x2e, 0x43, 0x6f, 0x6d, 0x6d, 0x61, 0x6e, 0x64, 0x2e, 0x54, 0x79, 0x70, 0x65, 0x52, 0x04, 0x74,
+	0x79, 0x70, 0x65, 0x12, 0x1f, 0x0a, 0x0b, 0x73, 0x75, 0x62, 0x5f, 0x63, 0x6f, 0x6d, 0x6d, 0x61,
+	0x6e, 0x64, 0x18, 0x02, 0x20, 0x01, 0x28, 0x0c, 0x52, 0x0a, 0x73, 0x75, 0x62, 0x43, 0x6f, 0x6d,
+	0x6d, 0x61, 0x6e, 0x64, 0x22, 0x75, 0x0a, 0x04, 0x54, 0x79, 0x70, 0x65, 0x12, 0x18, 0x0a, 0x14,
+	0x43, 0x4f, 0x4d, 0x4d, 0x41, 0x4e, 0x44, 0x5f, 0x54, 0x59, 0x50, 0x45, 0x5f, 0x55, 0x4e, 0x4b,
+	0x4e, 0x4f, 0x57, 0x4e, 0x10, 0x00, 0x12, 0x21, 0x0a, 0x1d, 0x43, 0x4f, 0x4d, 0x4d, 0x41, 0x4e,
+	0x44, 0x5f, 0x54, 0x59, 0x50, 0x45, 0x5f, 0x47, 0x45, 0x54, 0x5f, 0x4e, 0x4f, 0x44, 0x45, 0x5f,
+	0x41, 0x50, 0x49, 0x5f, 0x55, 0x52, 0x4c, 0x10, 0x01, 0x12, 0x18, 0x0a, 0x14, 0x43, 0x4f, 0x4d,
+	0x4d, 0x41, 0x4e, 0x44, 0x5f, 0x54, 0x59, 0x50, 0x45, 0x5f, 0x45, 0x58, 0x45, 0x43, 0x55, 0x54,
+	0x45, 0x10, 0x02, 0x12, 0x16, 0x0a, 0x12, 0x43, 0x4f, 0x4d, 0x4d, 0x41, 0x4e, 0x44, 0x5f, 0x54,
+	0x59, 0x50, 0x45, 0x5f, 0x51, 0x55, 0x45, 0x52, 0x59, 0x10, 0x03, 0x22, 0x60, 0x0a, 0x16, 0x43,
+	0x6f, 0x6d, 0x6d, 0x61, 0x6e, 0x64, 0x45, 0x78, 0x65, 0x63, 0x75, 0x74, 0x65, 0x52, 0x65, 0x73,
+	0x70, 0x6f, 0x6e, 0x73, 0x65, 0x12, 0x14, 0x0a, 0x05, 0x65, 0x72, 0x72, 0x6f, 0x72, 0x18, 0x01,
+	0x20, 0x01, 0x28, 0x09, 0x52, 0x05, 0x65, 0x72, 0x72, 0x6f, 0x72, 0x12, 0x30, 0x0a, 0x07, 0x72,
+	0x65, 0x73, 0x75, 0x6c, 0x74, 0x73, 0x18, 0x02, 0x20, 0x03, 0x28, 0x0b, 0x32, 0x16, 0x2e, 0x63,
+	0x6f, 0x6d, 0x6d, 0x61, 0x6e, 0x64, 0x2e, 0x45, 0x78, 0x65, 0x63, 0x75, 0x74, 0x65, 0x52, 0x65,
+	0x73, 0x75, 0x6c, 0x74, 0x52, 0x07, 0x72, 0x65, 0x73, 0x75, 0x6c, 0x74, 0x73, 0x22, 0x54, 0x0a,
+	0x14, 0x43, 0x6f, 0x6d, 0x6d, 0x61, 0x6e, 0x64, 0x51, 0x75, 0x65, 0x72, 0x79, 0x52, 0x65, 0x73,
+	0x70, 0x6f, 0x6e, 0x73, 0x65, 0x12, 0x14, 0x0a, 0x05, 0x65, 0x72, 0x72, 0x6f, 0x72, 0x18, 0x01,
+	0x20, 0x01, 0x28, 0x09, 0x52, 0x05, 0x65, 0x72, 0x72, 0x6f, 0x72, 0x12, 0x26, 0x0a, 0x04, 0x72,
+	0x6f, 0x77, 0x73, 0x18, 0x02, 0x20, 0x03, 0x28, 0x0b, 0x32, 0x12, 0x2e, 0x63, 0x6f, 0x6d, 0x6d,
+	0x61, 0x6e, 0x64, 0x2e, 0x51, 0x75, 0x65, 0x72, 0x79, 0x52, 0x6f, 0x77, 0x73, 0x52, 0x04, 0x72,
+	0x6f, 0x77, 0x73, 0x42, 0x22, 0x5a, 0x20, 0x67, 0x69, 0x74, 0x68, 0x75, 0x62, 0x2e, 0x63, 0x6f,
+	0x6d, 0x2f, 0x72, 0x71, 0x6c, 0x69, 0x74, 0x65, 0x2f, 0x72, 0x71, 0x6c, 0x69, 0x74, 0x65, 0x2f,
+	0x63, 0x6c, 0x75, 0x73, 0x74, 0x65, 0x72, 0x62, 0x06, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x33,
 }
 
 var (
@@ -191,19 +335,25 @@ func file_message_proto_rawDescGZIP() []byte {
 }
 
 var file_message_proto_enumTypes = make([]protoimpl.EnumInfo, 1)
-var file_message_proto_msgTypes = make([]protoimpl.MessageInfo, 2)
+var file_message_proto_msgTypes = make([]protoimpl.MessageInfo, 4)
 var file_message_proto_goTypes = []interface{}{
-	(Command_Type)(0), // 0: Command.Type
-	(*Address)(nil),   // 1: Address
-	(*Command)(nil),   // 2: Command
+	(Command_Type)(0),              // 0: cluster.Command.Type
+	(*Address)(nil),                // 1: cluster.Address
+	(*Command)(nil),                // 2: cluster.Command
+	(*CommandExecuteResponse)(nil), // 3: cluster.CommandExecuteResponse
+	(*CommandQueryResponse)(nil),   // 4: cluster.CommandQueryResponse
+	(*command.ExecuteResult)(nil),  // 5: command.ExecuteResult
+	(*command.QueryRows)(nil),      // 6: command.QueryRows
 }
 var file_message_proto_depIdxs = []int32{
-	0, // 0: Command.type:type_name -> Command.Type
-	1, // [1:1] is the sub-list for method output_type
-	1, // [1:1] is the sub-list for method input_type
-	1, // [1:1] is the sub-list for extension type_name
-	1, // [1:1] is the sub-list for extension extendee
-	0, // [0:1] is the sub-list for field type_name
+	0, // 0: cluster.Command.type:type_name -> cluster.Command.Type
+	5, // 1: cluster.CommandExecuteResponse.results:type_name -> command.ExecuteResult
+	6, // 2: cluster.CommandQueryResponse.rows:type_name -> command.QueryRows
+	3, // [3:3] is the sub-list for method output_type
+	3, // [3:3] is the sub-list for method input_type
+	3, // [3:3] is the sub-list for extension type_name
+	3, // [3:3] is the sub-list for extension extendee
+	0, // [0:3] is the sub-list for field type_name
 }
 
 func init() { file_message_proto_init() }
@@ -236,6 +386,30 @@ func file_message_proto_init() {
 				return nil
 			}
 		}
+		file_message_proto_msgTypes[2].Exporter = func(v interface{}, i int) interface{} {
+			switch v := v.(*CommandExecuteResponse); i {
+			case 0:
+				return &v.state
+			case 1:
+				return &v.sizeCache
+			case 2:
+				return &v.unknownFields
+			default:
+				return nil
+			}
+		}
+		file_message_proto_msgTypes[3].Exporter = func(v interface{}, i int) interface{} {
+			switch v := v.(*CommandQueryResponse); i {
+			case 0:
+				return &v.state
+			case 1:
+				return &v.sizeCache
+			case 2:
+				return &v.unknownFields
+			default:
+				return nil
+			}
+		}
 	}
 	type x struct{}
 	out := protoimpl.TypeBuilder{
@@ -243,7 +417,7 @@ func file_message_proto_init() {
 			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
 			RawDescriptor: file_message_proto_rawDesc,
 			NumEnums:      1,
-			NumMessages:   2,
+			NumMessages:   4,
 			NumExtensions: 0,
 			NumServices:   0,
 		},
diff --git a/cluster/message.proto b/cluster/message.proto
index 270e837a..bd59373c 100644
--- a/cluster/message.proto
+++ b/cluster/message.proto
@@ -1,4 +1,7 @@
 syntax = "proto3";
+package cluster;
+
+import "command/command.proto";
 
 option go_package = "github.com/rqlite/rqlite/cluster";
 
@@ -10,6 +13,19 @@ message Command {
     enum Type {
         COMMAND_TYPE_UNKNOWN = 0;
         COMMAND_TYPE_GET_NODE_API_URL = 1;
+        COMMAND_TYPE_EXECUTE = 2;
+        COMMAND_TYPE_QUERY = 3;
     }
     Type type = 1;
+    bytes sub_command = 2;
+}
+
+message CommandExecuteResponse {
+	string error = 1;
+	repeated command.ExecuteResult results = 2;
+}
+
+message CommandQueryResponse {
+	string error = 1;
+	repeated command.QueryRows rows = 2;
 }
diff --git a/cluster/service.go b/cluster/service.go
index d96748df..e6c7fb56 100644
--- a/cluster/service.go
+++ b/cluster/service.go
@@ -13,6 +13,7 @@ import (
 	"time"
 
 	"github.com/golang/protobuf/proto"
+	"github.com/rqlite/rqlite/command"
 )
 
 // stats captures stats for the Cluster service.
@@ -21,6 +22,8 @@ var stats *expvar.Map
 const (
 	numGetNodeAPIRequest  = "num_get_node_api_req"
 	numGetNodeAPIResponse = "num_get_node_api_resp"
+	numExecuteRequest     = "num_execute_req"
+	numQueryRequest       = "num_query_req"
 )
 
 const (
@@ -35,6 +38,8 @@ func init() {
 	stats = expvar.NewMap("cluster")
 	stats.Add(numGetNodeAPIRequest, 0)
 	stats.Add(numGetNodeAPIResponse, 0)
+	stats.Add(numExecuteRequest, 0)
+	stats.Add(numQueryRequest, 0)
 }
 
 // Dialer is the interface dialers must implement.
@@ -44,6 +49,21 @@ type Dialer interface {
 	Dial(address string, timeout time.Duration) (net.Conn, error)
 }
 
+// Database is the interface any queryable system must implement
+type Database interface {
+	// Execute executes a slice of queries, each of which is not expected
+	// to return rows. If timings is true, then timing information will
+	// be return. If tx is true, then either all queries will be executed
+	// successfully or it will as though none executed.
+	Execute(er *command.ExecuteRequest) ([]*command.ExecuteResult, error)
+
+	// Query executes a slice of queries, each of which returns rows. If
+	// timings is true, then timing information will be returned. If tx
+	// is true, then all queries will take place while a read transaction
+	// is held on the database.
+	Query(qr *command.QueryRequest) ([]*command.QueryRows, error)
+}
+
 // Transport is the interface the network layer must provide.
 type Transport interface {
 	net.Listener
@@ -55,6 +75,8 @@ type Service struct {
 	tn   Transport // Network layer this service uses
 	addr net.Addr  // Address on which this service is listening
 
+	db Database // The queryable system.
+
 	mu      sync.RWMutex
 	https   bool   // Serving HTTPS?
 	apiAddr string // host:port this node serves the HTTP API.
@@ -63,10 +85,11 @@ type Service struct {
 }
 
 // New returns a new instance of the cluster service
-func New(tn Transport) *Service {
+func New(tn Transport, db Database) *Service {
 	return &Service{
 		tn:     tn,
 		addr:   tn.Addr(),
+		db:     db,
 		logger: log.New(os.Stderr, "[cluster] ", log.LstdFlags),
 	}
 }
@@ -173,5 +196,56 @@ func (s *Service) handleConn(conn net.Conn) {
 		}
 		conn.Write(b)
 		stats.Add(numGetNodeAPIResponse, 1)
+
+	case Command_COMMAND_TYPE_EXECUTE:
+		stats.Add(numExecuteRequest, 1)
+
+		er := &command.ExecuteRequest{}
+		if err = proto.Unmarshal(c.SubCommand, er); err != nil {
+			// Write some error, then close?
+			return
+		}
+
+		resp := &CommandExecuteResponse{}
+		res, err := s.db.Execute(er)
+		if err != nil {
+			resp.Error = err.Error()
+		} else {
+			resp.Results = make([]*command.ExecuteResult, len(res))
+			for i := range res {
+				resp.Results[i] = res[i]
+			}
+		}
+		b, err = proto.Marshal(resp)
+		if err != nil {
+			return
+		}
+		conn.Write(b)
+
+	case Command_COMMAND_TYPE_QUERY:
+		stats.Add(numQueryRequest, 1)
+		return
+
+		qr := &command.QueryRequest{}
+		if err = proto.Unmarshal(c.SubCommand, qr); err != nil {
+			// Write some error, then close?
+			return
+		}
+
+		resp := &CommandQueryResponse{}
+		res, err := s.db.Query(qr)
+		if err != nil {
+			resp.Error = err.Error()
+		} else {
+			resp.Rows = make([]*command.QueryRows, len(res))
+			for i := range res {
+				resp.Rows[i] = res[i]
+			}
+		}
+		b, err = proto.Marshal(resp)
+		if err != nil {
+			return
+		}
+		conn.Write(b)
 	}
 }
diff --git a/cluster/service_mux_test.go b/cluster/service_mux_test.go
index 409d3478..1555e2b0 100644
--- a/cluster/service_mux_test.go
+++ b/cluster/service_mux_test.go
@@ -15,7 +15,7 @@ func Test_NewServiceSetGetNodeAPIAddrMuxed(t *testing.T) {
 	go mux.Serve()
 	tn := mux.Listen(1) // Could be any byte value.
 
-	s := New(tn)
+	s := New(tn, mustNewMockDatabase())
 	if s == nil {
 		t.Fatalf("failed to create cluster service")
 	}
@@ -49,7 +49,7 @@ func Test_NewServiceSetGetNodeAPIAddrMuxedTLS(t *testing.T) {
 	go mux.Serve()
 	tn := mux.Listen(1) // Could be any byte value.
 
-	s := New(tn)
+	s := New(tn, mustNewMockDatabase())
 	if s == nil {
 		t.Fatalf("failed to create cluster service")
 	}
diff --git a/cluster/service_test.go b/cluster/service_test.go
index 0591a6e3..2829f3bb 100644
--- a/cluster/service_test.go
+++ b/cluster/service_test.go
@@ -7,12 +7,13 @@ import (
 	"testing"
 	"time"
 
+	"github.com/rqlite/rqlite/command"
 	"github.com/rqlite/rqlite/testdata/x509"
 )
 
 func Test_NewServiceOpenClose(t *testing.T) {
 	ml := mustNewMockTransport()
-	s := New(ml)
+	s := New(ml, mustNewMockDatabase())
 	if s == nil {
 		t.Fatalf("failed to create cluster service")
 	}
@@ -30,7 +31,7 @@ func Test_NewServiceOpenClose(t *testing.T) {
 
 func Test_NewServiceSetGetAPIAddr(t *testing.T) {
 	ml := mustNewMockTransport()
-	s := New(ml)
+	s := New(ml, mustNewMockDatabase())
 	if s == nil {
 		t.Fatalf("failed to create cluster service")
 	}
@@ -51,7 +52,7 @@ func Test_NewServiceSetGetAPIAddr(t *testing.T) {
 
 func Test_NewServiceSetGetNodeAPIAddr(t *testing.T) {
 	ml := mustNewMockTransport()
-	s := New(ml)
+	s := New(ml, mustNewMockDatabase())
 	if s == nil {
 		t.Fatalf("failed to create cluster service")
 	}
@@ -89,7 +90,7 @@ func Test_NewServiceSetGetNodeAPIAddr(t *testing.T) {
 
 func Test_NewServiceSetGetNodeAPIAddrTLS(t *testing.T) {
 	ml := mustNewMockTLSTransport()
-	s := New(ml)
+	s := New(ml, mustNewMockDatabase())
 	if s == nil {
 		t.Fatalf("failed to create cluster service")
 	}
@@ -130,24 +131,6 @@ type mockTransport struct {
 	remoteEncrypted bool
 }
 
-func mustNewMockTransport() *mockTransport {
-	tn, err := net.Listen("tcp", "localhost:0")
-	if err != nil {
-		panic("failed to create mock listener")
-	}
-	return &mockTransport{
-		tn: tn,
-	}
-}
-
-func mustNewMockTLSTransport() *mockTransport {
-	tn := mustNewMockTransport()
-	return &mockTransport{
-		tn:              tls.NewListener(tn, mustCreateTLSConfig()),
-		remoteEncrypted: true,
-	}
-}
-
 func (ml *mockTransport) Accept() (c net.Conn, err error) {
 	return ml.tn.Accept()
 }
@@ -177,6 +160,41 @@ func (ml *mockTransport) Dial(addr string, timeout time.Duration) (net.Conn, err
 	return conn, err
 }
 
+func mustNewMockTransport() *mockTransport {
+	tn, err := net.Listen("tcp", "localhost:0")
+	if err != nil {
+		panic("failed to create mock listener")
+	}
+	return &mockTransport{
+		tn: tn,
+	}
+}
+
+func mustNewMockTLSTransport() *mockTransport {
+	tn := mustNewMockTransport()
+	return &mockTransport{
+		tn:              tls.NewListener(tn, mustCreateTLSConfig()),
+		remoteEncrypted: true,
+	}
+}
+
+type mockDatabase struct {
+	executeFn func(er *command.ExecuteRequest) ([]*command.ExecuteResult, error)
+	queryFn   func(qr *command.QueryRequest) ([]*command.QueryRows, error)
+}
+
+func (m *mockDatabase) Execute(er *command.ExecuteRequest) ([]*command.ExecuteResult, error) {
+	return m.executeFn(er)
+}
+
+func (m *mockDatabase) Query(qr *command.QueryRequest) ([]*command.QueryRows, error) {
+	return m.queryFn(qr)
+}
+
+func mustNewMockDatabase() *mockDatabase {
+	return &mockDatabase{}
+}
+
 func mustCreateTLSConfig() *tls.Config {
 	var err error