At Thu, 1 Oct 2020 12:58:19 +0900, Fujii Masao <masao.fujii@oss.nttdata.com> wrote in
> the table needs to be rewriitten. One idea for that is to improve that
> command
> so that it skips the table rewrite if wal_level=minimal.
> Of course, also you can change wal_level after marking the table as
> unlogged.
tablecmd.c:
> * There are two reasons for requiring a rewrite when changing
> * persistence: on one hand, we need to ensure that the buffers
> * belonging to each of the two relations are marked with or without
> * BM_PERMANENT properly. On the other hand, since rewriting creates
> * and assigns a new relfilenode, we automatically create or drop an
> * init fork for the relation as appropriate.
According to this comment, perhaps we can do that at least for
wal_level=minimal.
regards.
--
Kyotaro Horiguchi
NTT Open Source Software Center