On 2018-Nov-09, Jürgen Strobel wrote: > Regarding your example, what I expected is that *both* inserts would > consistently result in a tuple of (1, 42) since p should route the > insert to p1 and use p1's defaults. The current inconsistent behavior is > the heart of the bug.
I think that would be sensible behavior, as long as the partition doesn't override values for the partitioning column -- i.e. if the default values don't re-route the tuple to another partition, I think we should use the partition's default rather than the parent. This says we should expand defaults after routing. However, can we really route if we haven't expanded defaults? In general, we may be lacking values for some columns of the partition key. Another point: if we've already expanded defaults when processing at the parent level, when we reach the partition we don't know which values are still missing default expansion, or which defaults coming from the parent ought to be re-expanded. So this looks to be a bit of a landmine. In any case it seems really hard to see this is as a bug that we would fix in back-branches. -- Álvaro Herrera https://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
