Re: Dependences records and comments

=?utf-8?B?0JTQvNC40YLRgNC40Lkg0JLQvtGA0L7QvdC40L0=?= <carriingfate92(at)yandex(dot)ru> writes:
> When we create/alter object we already add dependency row to pg_depend
> (or, pg_shdepend) table for object that is depends (e.g. trigger depends
> on table which it created). But when I add comment on table, no one
> dependency row is added. Why?

Comments aren't interesting for dependency purposes: nothing can depend
on a comment, nor does a comment depend on anything but its one owning
object, they aren't relevant for CASCADE/RESTRICT rules, etc. So
tracking them in pg_depend would just bloat pg_depend for little gain.
It's simpler to have hard-wired logic to look for a comment and delete it
when any object is deleted.

regards, tom lane