presto-orc/src/main/java/io/prestosql/orc/writer/SliceDictionaryColumnWriter.java/SliceDictionaryColumnWriter/reset
class SliceDictionaryColumnWriter:    @Override
    public void reset()
    {
        checkState(closed);
        closed = false;
        dataStream.reset();
        presentStream.reset();
        dictionaryDataStream.reset();
        dictionaryLengthStream.reset();
        rowGroups.clear();
        rowGroupValueCount = 0;
        statisticsBuilder = newStringStatisticsBuilder();
        columnEncoding = null;

        dictionary.clear();
        rawBytes = 0;
        totalValueCount = 0;
        totalNonNullValueCount = 0;

        if (directEncoded) {
            directEncoded = false;
            directColumnWriter.reset();
        }
    }