the Google Dremel paper. In Parquet, data in a single column is stored contiguously.
Apache Parquet is a columnar data storage format, specifically designed for big data storage and processing. It is based on record shredding and the assembly algorithm from the Google Dremel paper. In Parquet, data in a single column is stored contiguously. The columnar format gives Parquet some unique benefits. For example, if you have a table with 100 columns and you mostly access 10 columns in a row-based format, you will have to load all the 100 columns, as the granularity level is at the row level. But, in Parquet, you will only need to load 10 columns. Another benefit is that since all of the data in a given column is of the same datatype (by definition), compression is much more efficient.
While we are discussing Parquet and its merits, it's a good idea to discuss the economic reason behind Parquet's success. There are two factors that every practitioner would like to...