On Tue, Jun 15, 2021 at 07:53:26AM +0200, Peter Eisentraut wrote: > On 15.06.21 07:37, Michael Paquier wrote: > > > > Actually, I was just thinking that default yes/no/on/off stuff maybe > > > > should be > > > > defined to mean "lz4" rather than meaning pglz for "backwards > > > > compatibility". > > > +1 > > I am not sure that we have any reasons to be that aggressive about > > this one either, and this would mean that wal_compression=on implies a > > different method depending on the build options. I would just stick > > with the past, careful practice that we have to use a default > > backward-compatible value as default, while being able to use a new > > option.
You're right, I hadn't though this through all the way. There's precedent if the default is non-static (wal_sync_method). But I think yes/on/true/1 should be a compatibility alias for a static thing, and then the only option is pglz. Of course, changing the default to LZ4 is still a possibility. > If we think this new thing is strictly better than the old thing, then why > not make it the default. What would be the gain from sticking to the old > default? > > The point that the default would depend on build options is a valid one. > I'm not sure whether it's important enough by itself.
