The way this is supposed to go is someone submits a patch and they receive feedback, then act on that feedback. If I was able to get away with deflecting all review comments with a simple "you fix it if you don't like it" there would be considerably more patches with my name on it accepted, but probably no further forward in real terms because of the loose ends it creates.
Fair enough.
It's just that people keep saying that this is easy, and have said so for a long time, but nobody has written a patch for it.
In this case, simply changing the default will remove a whole class of performance optimization that we have educated people to expect. I'm sorry to point this out but removing that will cause many real changes for people's systems that we will not be thanked for, even though I understand your reasoning and wish the same goals to be achieved.
My claim here is that a lot *fewer* people have come to expect this performance optimization, than would (quite reasonably) expect that backups should work on a system without taking it down for restart to reconfigure it to support that.
I run into that all the time. I hear complaints about that all the time. I have not heard a single user complain about performance loss after enabling backups.
And how many people that rely on this optimization don't do any *other* optimization on their system *anyway*, that would cause them to require a restart anyway? It's not like we're taking away their ability to enable the optimization, it's just not on by default.
I'm willing to assist in a project to allow changing wal_level online in this release. Please let's follow that path.
Sure thing, I will be happy to help test and review such a patch.
I will still argue that the *default* should be wal_level=replica though. Because once we have such a patch, it's trivial to re-enable this performance optimization (at the cost of backups and replication).