Make the transaction snapshot ID an ATTACH parameter

[mdeville]

Hello !

I recently encountered a need where I wanted to COPY multiple tables within the same transaction snapshot ID.
As I understand it, duckdb already uses transaction snapshots to copy a single table in parallel.

The idea is to add another PostgreSQL specific option to the ATTACH command which would always use the given transaction snapshot when calling the function PostgresScanConnect.

This would allow duckdb to take consistent snapshots of Postgres databases, which I believe is quite useful.

What do you think about this feature ?

Thanks a lot for the amazing software !

[mdeville]

If anyone wants something that kinda works I've made a fork with the following patch to add a new attach option SNAPSHOT_ID:

main...mdeville:duckdb-postgres:transactionsnapshot#files_bucket

The extension must be built manually from the branch transactionsnapshot and then you will have to run duckdb -unsigned to allow loading custom extensions