On 2021-Mar-21, Justin Pryzby wrote: > On Fri, Mar 19, 2021 at 10:57:37AM -0300, Alvaro Herrera wrote: > > > Also, it "fails to avoid" adding duplicate constraints: > > > > > > Check constraints: > > > "c" CHECK (i IS NOT NULL AND i > 1 AND i < 2) > > > "cc" CHECK (i IS NOT NULL AND i >= 1 AND i < 2) > > > "p1_check" CHECK (true) > > > "p1_i_check" CHECK (i IS NOT NULL AND i >= 1 AND i < 2) > > > > Do you mean the "cc" and "p1_i_check" one? I mean, if you already have > > No, I started with c and cc, and it added the broken constraint p1_check > (which > you say you've fixed) and the redundant constraint p1_i_check. I guess that's > what you meant.
Yes, that's what I meant. > > a constraint in the partition that duplicates the partition constraint, > > then during attach we still create our new constraint? I guess a > > solution to this would be to scan all constraints and see if any equals > > the expression that the new one would have. Sounds easy enough now that > > write it out loud. > > But it looks like DetachAddConstraintIfNeeded already intended to do that: > > + if (equal(constraintExpr, thisconstr)) > + return; Hah, so I had already done it, but forgot. > Actually, it appears your latest notpatch resolves both these issues. Great. > But note that it doesn't check if an existing constraint "implies" the new > constraint - maybe it should. Hm, I'm not sure I want to do that, because that means that if I later have to attach the partition again with the same partition bounds, then I might have to incur a scan to recheck the constraint. I think we want to make the new constraint be as tight as possible ... -- Álvaro Herrera 39°49'30"S 73°17'W
