RE: Implement UNLOGGED clause for COPY FROM

From: Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
> So you want your users to shutdown and restart the server before Copy
> because that would be required if you want to change the wal_level.

Yes. They seem to be fine with it, as far as I heard from a person who is involved in the system design.

> However, even if we do that, users who are running the server
> previously with wal_level as 'replica' won't be happy after doing this
> change. Because if they change the wal_level to 'none' for certain
> operations like bulk load and then again change back the mode to
> 'replica' they need to back up the database again to setup 'replica'
> as they can't continue replication from the previous point (consider
> update on a page for which previously WAL was not written).

Yes, it requires the database backup. The database backup should be a daily task anyway, so I expect it wouldn't impose extra maintenance burdon on the user. Plus, not all users use the streaming replication for HA. I think it's helpful for the maturing Postgres to provide some kind of solution for some context so that user can scratch their itches.

Regards
Takayuki Tsunakawa