Comment by medvezhenok

Yup, especially data backups (although I wouldn't store critical backups like this, only nice-to-have ones). One minor note is that parquet file sizes / compressed sizes can be sensitive to ordering, so you can try different sort orders to get optimal compression.

I found with using various tricks I can get the zstd parquet to be up to 10x (or more) smaller than an equivalent Postgres table - but obviously the exact compression ratios will depend on the kind of data you have and how well your Postgres table is normalized.