void MergeTreeReader::readData(
const String & name, const IDataType & type, IColumn & column,
size_t from_mark, bool continue_reading, size_t max_rows_to_read,
bool with_offsets)
{
IDataType::InputStreamGetter stream_getter = [&] (const IDataType::SubstreamPath & path) -> ReadBuffer *
{
/// If offsets for arrays have already been read.
if (!with_offsets && !path.empty() && path.back().type == IDataType::Substream::ArraySizes)
return nullptr;
String stream_name = IDataType::getFileNameForStream(name, path);
auto it = streams.find(stream_name);
if (it == streams.end())
return nullptr;
Stream & stream = *it->second;
if (!continue_reading)
stream.seekToMark(from_mark);
return stream.data_buffer;
};
double & avg_value_size_hint = avg_value_size_hints[name];
type.deserializeBinaryBulkWithMultipleStreams(column, stream_getter, max_rows_to_read, avg_value_size_hint, true, {});
IDataType::updateAvgValueSizeHint(column, avg_value_size_hint);
}
void TinyLogBlockInputStream::readData(const String & name, const IDataType & type, IColumn & column, UInt64 limit)
{
IDataType::DeserializeBinaryBulkSettings settings; /// TODO Use avg_value_size_hint.
settings.getter = [&] (const IDataType::SubstreamPath & path) -> ReadBuffer *
{
String stream_name = IDataType::getFileNameForStream(name, path);
if (!streams.count(stream_name))
streams[stream_name] = std::make_unique<Stream>(storage.files[stream_name].data_file.path(), max_read_buffer_size);
return &streams[stream_name]->compressed;
};
if (deserialize_states.count(name) == 0)
type.deserializeBinaryBulkStatePrefix(settings, deserialize_states[name]);
type.deserializeBinaryBulkWithMultipleStreams(column, limit, settings, deserialize_states[name]);
}
