On Mon, Jan 2, 2017 at 10:48 AM, Simon Riggs <si...@2ndquadrant.com> wrote:
> On 2 January 2017 at 09:39, Magnus Hagander <mag...@hagander.net> wrote: > > > Please do submit a patch for it. > > 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). //Magnus
