Hi, On 2018-08-25 14:47:20 -0400, Bruce Momjian wrote: > Well, our normal logical is whether the average user would adjust their > behavior based on this change, or whether it is user visible. I thought > it was a contrived-enough query that this was not the case, but I would > be interested to hear what others think.
I think that's less "our" logic and more yours, that has become established because you've done most of the major release notes for a long time. I'm not trying to say that that's wrong or anything, just that a lot of those principles grew organically without explicit decisions. I also think that the need of userbase have shifted - it used to be that a lot more people couldn't migrate to PG for lack of features, but these days we have a much larger userbase that has to migrate from version to version on a regular basis. Planner changes, in my experience, are *the* major hurdle in doing so (leaving aside things like the 8.3 casting changes), because they have the potential to drastically change performance. In a largely unpredictable way. So one of the first things you do after encountering an issue while testing an issue during a migration, is to look through the release notes whether that query could be affected by a documented change. Greetings, Andres Freund