Last time we've discovered different encoding methods available in Apache Parquet. But the encoding is not the single technique helping to reduce the size of files. The other one, very similar, is the compression.
Working with nested structures appears as a problem in column-oriented storage. However, thanks to Google's Dremel solution, this task can be solved efficiently.
An efficient data storage is one of success keys of a good storage format. One of methods helping to improve that is an appropriate encoding and Parquet comes with several different methods.
When I've started to play with Apache Parquet I was surprised about 2 versions of writers. Before approaching the rest of planed topics, it's a good moment to explain these different versions better.
Previously we focused on types available in Parquet. This time we can move forward and analyze how the framework stores the data in the files.
Data in Apache Parquet files is written against specific schema. And who tells schema, invokes automatically data types for the fields composing this schema.
Very often an appropriate storage is as important as the data processing pipeline. And among different possibilities we can still store the data in files. Thanks to different formats, such as column-oriented ones, some of actions in reading path can be optimized.
