On Mon, Mar 7, 2016 at 3:17 AM, Shulgin, Oleksandr <oleksandr.shulgin@zalando.de> wrote: > > 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.
People with meticulous standards are expected to re-validate their application, including plans and performance, before doing major version updates into production. They can continue to use a *fully patched* server from a previous major release while they do that.
This is not the case for minor version updates. We do not want to put people in the position where getting a security or corruption-risk update forces them to also accept changes which may destroy the performance of their system.
I don't know if it is set out somewhere else, but there are many examples in this list of us declining to back-patch performance bug fixes which might negatively impact some users. The only times we have done it that I can think of are when there is almost no conceivable way it could have a meaningful negative effect, or if the bug was tied in with security or stability bugs that needed to be fixed anyway and couldn't be separated.
The necessity to perform security upgrades is indeed a valid argument against back-patching this, since this is not a bug that causes incorrect results or data corruption, etc.
