> importing them into postgres shouldn't be that long and then you can do the same or more than with DuckDB.

Usually new data is generated regularly and would require creating a separate ETL process to ingest into Postgres. With DuckDB, no ETL is needed. New Parquet files are just read off the disk.

> Also as a side note, is everyone just using DuckDB in memory?

DuckDB is generally used as a single-user, and yes in-memory use case is most common. Not sure about use cases where a single user requires multiple sessions? But DuckDB does have read concurrency, session isolation etc. I believe write serialization is supported in multiple sessions.

With Parquet files, it's append-only so the "write" use-cases tend to be more limited. Generally another process generates those Parquet files. DuckDB just works with them.