fdw: Parquet foreign data wrapper (write support)

[mfussenegger]

Problem Statement

If #15721 gets implemented then CrateDB has no capabilities to write or export the data into a parquet file.

If a user wants to use the FDW functionality to gain read-access to archived data, or to some sort of cheaper cold storage system they'd need to export the data into another format (e.g. using COPY TO JSON/CSV) or by using another client like crash - and then convert that data into a parquet file manually.

Possible Solutions

Implement write support for the Parquet foreign data wrapper. This would allow users to export the data using SQL statements like insert into <foreign_table> (...) (select ...).

Considered Alternatives

• COPY TO Parquet