> it'll only read in the files that have a max_age greater than 90. Data skipping is one of the best performance benefits. Actually Parquet files have a chunk

> it'll only read in the files that have a max_age greater than 90. Data skipping is one of the best performance benefits. Actually Parquet files have a chunked structure, with maybe 200 row groups in a large Parquet file. The metadata is stored per chunk in the file footer. So if that suggests you only need a few chunks with a file, your data reads can be orders of magnitude faster. The data is stored column wise too. So if you only need a few of the columns, you can get another 10x increase in performance. It's like magic, if your data is ordered in a way that can exploit this.