presto-hive/src/main/java/io/prestosql/plugin/hive/HivePageSink.java/HivePageSink/getDataPage
class HivePageSink:    private Page getDataPage(Page page)
    {
        Block[] blocks = new Block[dataColumnInputIndex.length];
        for (int i = 0; i < dataColumnInputIndex.length; i++) {
            int dataColumn = dataColumnInputIndex[i];
            blocks[i] = page.getBlock(dataColumn);
        }
        return new Page(page.getPositionCount(), blocks);
    }