Re: Fixing findDependentObjects()'s dependency on scan order (regressions in DROP diagnostic messages)

On 14.11.2018 11:28, Peter Geoghegan wrote:
> We're already relying on the scan order being in reverse chronological
> order, so we might as well formalize the dependency. I don't think
> that it's possible to sort the pg_depend entries as a way of fixing
> the breakage while avoiding storing this extra information -- what is
> there to sort on that's there already? You'd have to infer a whole
> bunch of things about the object types associated with pg_depend
> entries to do that, and teach dependency.c about its callers. That
> seems pretty brittle to me.

This solution changes pg_depend relation for solve a problem, which 
exists only in regression tests.  Very rarely it can be in the 
partitioning cases. Or is it not?
I think this decision is some excessive.
May be you consider another approach:
1. Order of dependencies in 'DROP ... CASCADE' case is a problem of test 
tools, not DBMS. And here we can use 'verbose terse'.
2. Print all dependencies in findDependentObjects() on a drop error (see 
attachment as a prototype).

-- 
Andrey Lepikhov
Postgres Professional
https://postgrespro.com
The Russian Postgres Company