Re: BUG #10675: alter database set tablespace and unlogged table

Andres Freund <andres@2ndquadrant.com> writes:
> I think one reason for the separate flag is that the checkpoint
> performed by pg_start_backup/pg_basebackup shouldn't just become more
> expensive because unlogged tables are needlessly flushed to disk. After
> all, unlogged tables are used because normal tables have a too high
> overhead in that scenario.

AFAIK, the "overhead" that unlogged tables are trying to avoid is WAL
I/O.  Nobody has argued (until this thread) that we are worried about
whether checkpoints write them.

            regards, tom lane