On Thu, Mar 3, 2016 at 2:48 AM, Shulgin, Oleksandr <oleksandr.shulgin@zalando.de> wrote: > On Wed, Mar 2, 2016 at 7:33 PM, Alvaro Herrera <alvherre@2ndquadrant.com> > wrote: >> Shulgin, Oleksandr wrote: >> >> > Alright. I'm attaching the latest version of this patch split in two >> > parts: the first one is NULLs-related bugfix and the second is the >> > "improvement" part, which applies on top of the first one. >> >> So is this null-related bugfix supposed to be backpatched? (I assume >> it's not because it's very likely to change existing plans). > > For the good, because cardinality estimations will be more accurate in these > cases, so yes I would expect it to be back-patchable.
-1. I think the cost of changing existing query plans in back branches is too high. The people who get a better plan never thank us, but the people who (by bad luck) get a worse plan always complain.
They might get that different plan when they upgrade to the latest major version anyway. Is it set somewhere that minor version upgrades should never affect the planner? I doubt so.
