Re: max_slot_wal_keep_size comment in postgresql.conf

At Tue, 26 May 2020 22:56:39 -0400, Isaac Morland <isaac(dot)morland(at)gmail(dot)com> wrote in
> On Tue, 26 May 2020 at 21:46, Kyotaro Horiguchi <horikyota(dot)ntt(at)gmail(dot)com>
> wrote:
>
> > At Tue, 26 May 2020 09:10:40 -0400, Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
> > wrote in
> > > In postgresql.conf, it says:
> > >
> > > #max_slot_wal_keep_size = -1 # measured in bytes; -1 disables
> > >
> > > I don't know if that is describing the dimension of this parameter or the
> > > units of it, but the default units for it are megabytes, not individual
> > > bytes, so I think it is pretty confusing.
> >
> > Agreed. It should be a leftover at the time the unit was changed
> > (before committed) to MB from bytes. The default value makes the
> > confusion worse.
> >
> > Is the following works?
> >
> > #max_slot_wal_keep_size = -1 # in MB; -1 disables
>
>
> Extreme pedant question: Is it MB (10^6 bytes) or MiB (2^20 bytes)?

GUC variables for file/memory sizes are in a traditional
representation, that is, a power of two represented by
SI-prefixes. AFAICS PostgreSQL doesn't use binary-prefixed units.

regards.

--
Kyotaro Horiguchi
NTT Open Source Software Center