func (self *LevelDbDatastore) fetchSinglePoint(database, series string, fields []*Field,
query *parser.SelectQuery) (*protocol.Series, error) {
fieldCount := len(fields)
fieldNames := make([]string, 0, fieldCount)
point := &protocol.Point{Values: make([]*protocol.FieldValue, 0, fieldCount)}
timestampBuffer := bytes.NewBuffer(make([]byte, 0, 8))
sequenceNumberBuffer := bytes.NewBuffer(make([]byte, 0, 8))
timestamp := common.TimeToMicroseconds(query.GetStartTime())
sequenceNumber, err := query.GetSinglePointQuerySequenceNumber()
if err != nil {
return nil, err
}
binary.Write(timestampBuffer, binary.BigEndian, self.convertTimestampToUint(×tamp))
binary.Write(sequenceNumberBuffer, binary.BigEndian, sequenceNumber)
sequenceNumber_uint64 := uint64(sequenceNumber)
point.SequenceNumber = &sequenceNumber_uint64
point.SetTimestampInMicroseconds(timestamp)
for _, field := range fields {
pointKey := append(append(field.Id, timestampBuffer.Bytes()...), sequenceNumberBuffer.Bytes()...)
if data, err := self.db.Get(self.readOptions, pointKey); err != nil {
return nil, err
} else {
fieldValue := &protocol.FieldValue{}
err := proto.Unmarshal(data, fieldValue)
if err != nil {
return nil, err
}
if data != nil {
fieldNames = append(fieldNames, field.Name)
point.Values = append(point.Values, fieldValue)
}
}
}
result := &protocol.Series{Name: &series, Fields: fieldNames, Points: []*protocol.Point{point}}
return result, nil
}
