Robert Haas <robertmh...@gmail.com> writes: > On Wed, Mar 7, 2018 at 6:43 PM, Michael Paquier <mich...@paquier.xyz> wrote: >> On Wed, Mar 07, 2018 at 06:39:32PM -0500, Tom Lane wrote: >>> OK, seems like I'm on the short end of that vote. I propose to push the >>> GUC-crosschecking patch I posted yesterday, but not the default-value >>> change, and instead push Kyotaro-san's initdb change. Should we back-patch >>> these things to v10 where the problem appeared?
>> I would vote for a backpatch. If anybody happens to run initdb on v10 >> and gets max_connections to 10, that would immediately cause a failure. >> We could also wait for sombody to actually complain about that, but a >> bit of prevention does not hurt to ease future user experience on this >> released version. > In theory, back-patching the GUC-crosschecking patch could cause the > cluster to fail to restart after the upgrade. It's pretty unlikely. > We have to postulate someone with, say, default values but for > max_connections=12. But it's not impossible. I would be inclined to > back-patch the increase in the max_connections fallback from 10 to 20 > because that fixes a real, if unlikely, failure mode, but treat the > GUC cross-checking stuff as a master-only improvement. Although it's > unlikely to hurt many people, there's no real upside. Nobody is going > to say "boy, it's a good thing they tidied that GUC cross-checking in > the latest major release -- that really saved my bacon!". Nothing is > really broken as things stand. Done that way. I concur that there's little reason to back-patch the cross-check change before v10, since the case was even less likely to happen back when max_wal_senders defaulted to zero. There's some argument for changing it in v10, but avoiding thrashing translatable strings in a released branch probably outweighs it. regards, tom lane