Implement codec's encode

database.go

@@ -182,72 +182,6 @@ func (m *Measurement) FieldByName(name string) *Field {
 	return nil
 }
 
-// EncodeFields encodes a set of field ids and values to a byte slice.
-func (m *Measurement) EncodeFields(values map[uint8]interface{}) []byte {
-	// Sort fields for consistency.
-	fieldIDs := make([]uint8, 0, len(values))
-	for fieldID := range values {
-		fieldIDs = append(fieldIDs, fieldID)
-	}
-	sort.Sort(uint8Slice(fieldIDs))
-
-	// Allocate byte slice and write field count.
-	b := make([]byte, 1, 10)
-	b[0] = byte(len(values))
-
-	// Write out each field.
-	for _, fieldID := range fieldIDs {
-		var buf []byte
-
-		field := m.Field(fieldID)
-		if field == nil {
-			panic(fmt.Sprintf("field ID %d has no mapping", fieldID))
-		}
-		switch field.Type {
-		case influxql.Number:
-			v := values[fieldID]
-			// Convert integers to floats.
-			if intval, ok := v.(int); ok {
-				v = float64(intval)
-			}
-
-			buf = make([]byte, 9)
-			binary.BigEndian.PutUint64(buf[1:9], math.Float64bits(v.(float64)))
-		case influxql.Boolean:
-			v := values[fieldID].(bool)
-
-			// Only 1 byte need for a boolean.
-			buf = make([]byte, 2)
-			if v {
-				buf[1] = byte(1)
-			}
-		case influxql.String:
-			v := values[fieldID].(string)
-			if len(v) > maxStringLength {
-				v = v[:maxStringLength]
-			}
-			// Make a buffer for field ID, the string length, and the string.
-			buf = make([]byte, len(v)+3)
-
-			// Set the string length, then copy the string itself.
-			binary.BigEndian.PutUint16(buf[1:3], uint16(len(v)))
-			for k, v := range []byte(v) {
-				buf[k+3] = byte(v)
-			}
-		default:
-			panic(fmt.Sprintf("unsupported value type: %T", values[fieldID]))
-		}
-
-		// Always set the field ID as the leading byte.
-		buf[0] = fieldID
-
-		// Append temp buffer to the end.
-		b = append(b, buf...)
-	}
-
-	return b
-}
-
 // DecodeFields decodes a byte slice into a set of field ids and values.
 func (m *Measurement) DecodeFields(b []byte) map[uint8]interface{} {
 	if len(b) == 0 {
@@ -349,27 +283,6 @@ func (m *Measurement) seriesByTags(tags map[string]string) *Series {
 	return m.series[string(marshalTags(tags))]
 }
 
-// mapValues converts a map of values with string keys to field id keys.
-//
-// If a field exists, but its type is different, return an error. If error is
-// nil, but at least 1 field has not been mapped, nil is returned as the map.
-func (m *Measurement) mapValues(values map[string]interface{}) (map[uint8]interface{}, error) {
-	other := make(map[uint8]interface{}, len(values))
-	for k, v := range values {
-		f := m.FieldByName(k)
-		if f == nil {
-			panic(fmt.Sprintf("field does not exist for %s", k))
-		} else if influxql.InspectDataType(v) != f.Type {
-			return nil, fmt.Errorf("field %s is not of type %s", k, f.Type)
-		} else {
-			other[f.ID] = v
-		}
-	}
-
-	// All fields exist, and are of the expected type.
-	return other, nil
-}
-
 func (m *Measurement) seriesIDsAndFilters(stmt *influxql.SelectStatement) (seriesIDs, map[uint32]influxql.Expr) {
 	seriesIdsToExpr := make(map[uint32]influxql.Expr)
 	if stmt.Condition == nil {
@@ -770,6 +683,105 @@ type Field struct {
 // Fields represents a list of fields.
 type Fields []*Field
 
+// FieldCodec providecs encoding and decoding functionality for the fields of a given
+// Measurement. It is a distinct type to avoid locking writes on this node while
+// potentially long-running queries are executing.
+//
+// It is not affected by changes to the Measurement object after codec creation.
+type FieldCodec struct {
+	fieldsByID   map[uint8]*Field
+	fieldsByName map[string]*Field
+}
+
+// NewFieldCodec returns a FieldCodec for the given Measurement. Must be called with
+// a RLock that protects the Measurement.
+func NewFieldCodec(m *Measurement) *FieldCodec {
+	fieldsByID := make(map[uint8]*Field, len(m.Fields))
+	fieldsByName := make(map[string]*Field, len(m.Fields))
+	for _, f := range m.Fields {
+		fieldsByID[f.ID] = f
+		fieldsByName[f.Name] = f
+	}
+	return &FieldCodec{fieldsByID: fieldsByID, fieldsByName: fieldsByName}
+}
+
+// EncodeFields converts a map of values with string keys to a byte slice of field
+// IDs and values.
+//
+// If a field exists in the codec, but its type is different, an error is returned. If
+// a field is not present in the codec, the system panics.
+func (f *FieldCodec) EncodeFields(values map[string]interface{}) ([]byte, error) {
+	// Allocate byte slice and write field count.
+	b := make([]byte, 1, 10)
+	b[0] = byte(len(values))
+
+	for k, v := range values {
+		field := f.fieldsByName[k]
+		if field == nil {
+			panic(fmt.Sprintf("field does not exist for %s", k))
+		} else if influxql.InspectDataType(v) != field.Type {
+			return nil, fmt.Errorf("field %s is not of type %s", k, field.Type)
+		}
+
+		var buf []byte
+
+		switch field.Type {
+		case influxql.Number:
+			var value float64
+			// Convert integers to floats.
+			if intval, ok := v.(int); ok {
+				value = float64(intval)
+			} else {
+				value = v.(float64)
+			}
+
+			buf = make([]byte, 9)
+			binary.BigEndian.PutUint64(buf[1:9], math.Float64bits(value))
+		case influxql.Boolean:
+			value := v.(bool)
+
+			// Only 1 byte need for a boolean.
+			buf = make([]byte, 2)
+			if value {
+				buf[1] = byte(1)
+			}
+		case influxql.String:
+			value := v.(string)
+			if len(value) > maxStringLength {
+				value = value[:maxStringLength]
+			}
+			// Make a buffer for field ID, the string length, and the string.
+			buf = make([]byte, len(value)+3)
+
+			// Set the string length, then copy the string itself.
+			binary.BigEndian.PutUint16(buf[1:3], uint16(len(value)))
+			for i, c := range []byte(value) {
+				buf[i+3] = byte(c)
+			}
+		default:
+			panic(fmt.Sprintf("unsupported value type: %T", v))
+		}
+
+		// Always set the field ID as the leading byte.
+		buf[0] = field.ID
+
+		// Append temp buffer to the end.
+		b = append(b, buf...)
+	}
+
+	return b, nil
+}
+
+// DecodeByID
+func (f *FieldCodec) DecodeByID(fieldId uint8, b []byte) (interface{}, error) {
+	return 0, nil
+}
+
+// DecodeByName
+func (f *FieldCodec) DecodeByName(fieldName uint8, b []byte) (interface{}, error) {
+	return 0, nil
+}
+
 // Series belong to a Measurement and represent unique time series in a database
 type Series struct {
 	ID   uint32

server.go

@@ -1662,15 +1662,23 @@ func (s *Server) writePoint(database, retentionPolicy string, point *Point) (uin
 		return 0, err
 	}
 
-	// Convert string-key/values to fieldID-key/values.
-	rawValues, err := m.mapValues(values)
+	// Get a field codec.
+	s.mu.RLock()
+	codec := NewFieldCodec(m)
+	s.mu.RUnlock()
+	if codec == nil {
+		panic("field codec is nil")
+	}
+
+	// Convert string-key/values to encoded fields.
+	encodedFields, err := codec.EncodeFields(values)
 	if err != nil {
 		return 0, err
 	}
 
 	// Encode point header.
 	data := marshalPointHeader(seriesID, timestamp.UnixNano())
-	data = append(data, m.EncodeFields(rawValues)...)
+	data = append(data, encodedFields...)
 
 	// Publish "raw write series" message on shard's topic to broker.
 	return s.client.Publish(&messaging.Message{