My Hacker News items table in ClickHouse has 47,428,860 items, and it's 5.82 GB compressed and 18.18 GB uncompressed. What makes Parquet compression worse here, when both formats are columnar?
My Hacker News items table in ClickHouse has 47,428,860 items, and it's 5.82 GB compressed and 18.18 GB uncompressed. What makes Parquet compression worse here, when both formats are columnar?
Sorting, compression algorithm +level, and data types can all have an impact. I noted elsewhere that a Boolean is getting represented as an integer. That’s one bit vs 1-4 bytes.
There is also flexibility in what you define as the dataset. Skinnier, but more focused tables could be space saving vs a wide table that covers everything -will probably break compressible runs of data.
Parquet has a few compression option. Not sure which one they are using.
Plus isn't the least wasteful format, native duckdb for instance compacts better. That's not just down to the compression algorithm, which as you say got three main options for parquet.
.. and Remove all the political shit-slop since COVID/AI and it's probably under a gig.