Columnar data storage not row-based unlike RDBMS (PAA + kay)
So Data Compression rate is high (due to similar data types in columns)
When writing Parquet files, all columns automatically allow null values for compatibility
Since columns store the same data type, each column can use encoding methods optimized for its specific data type
Parquet Notion
Parquet Tools
A 42 kB Parquet file can contain over 4 PB of data.