po 13. 7. 2020 v 11:11 odesílatel Pavel Stehule <pavel.steh...@gmail.com> napsal:
> Hi > > čt 18. 6. 2020 v 0:47 odesílatel David G. Johnston < > david.g.johns...@gmail.com> napsal: > >> This is a follow-up to Bug # 16492 which also links to a thread sent to >> -hackers back in 2018. >> >> I'm firmly of the belief that the existing behavior of DROP relation IF >> EXISTS is flawed - it should not be an error if there is a namespace >> collision but the relkind of the existing relation doesn't match the >> relkind set by the DROP command. >> >> Since our documentation fails to elaborate on any additional behavior, >> and uses the relkind in the description, our users (few as they may be) are >> rightly calling this a bug. I loosely believe that any behavior change in >> this area should not be back-patched thus for released versions this is a >> documentation bug. I have attached a patch to fix that bug. >> >> In putting together the patch I noticed that the existing drop_if_exists >> regression tests exercise the DROP DOMAIN command. Out of curiosity I >> included that in my namespace testing and discovered that DROP DOMAIN >> thinks of itself as being a relation for purposes of IF EXISTS but DROP >> TABLE does not. I modified both DROP DOMAIN and the Glossary in response >> to this finding - though I suspect to find disagreement with my choice. I >> looked at pg_class for some guidance but a quick search for RELKIND_ >> (DOMAIN) and finding nothing decided I didn't know enough and figured to >> punt on any further exploration of this inconsistency. >> >> The documentation and tests need to go in and be back-patched. After >> that happens I'll see whether and/or how to go about trying to get my PoV >> on the behavioral change committed. >> > > I am reading this patch. I don't think so text for domains and types are > correct (or minimally it is little bit messy) > > + This parameter instructs <productname>PostgreSQL</productname> to > search > + for the first instance of any relation with the provided name. > + If no relations are found a notice is issued and the command ends. > + If a relation is found then one of two things will happen: > + if the relation is an domain it is dropped, otherwise the command > fails. > > "If no relations are found ...". > > This case is a little bit more complex - domains are not subset of > relations. But relations (in Postgres) extends types. > > So in this case maybe modified text can be better > > + This parameter instructs <productname>PostgreSQL</productname> to > search > + for the first instance of any domain with the provided name in > pg_type catalog. > + If no type is found a notice is issued and the command ends. > + If a type is found then one of two things will happen: > + if the type is a domain it is dropped, otherwise the command fails. > Postgres knows > + base types, composite types, relation related types and domain > types. > create type footyp as (a int, b int); postgres=# drop domain if exists footyp; ERROR: "footyp" is not a domain postgres=# > Regards > > Pavel > > > > > >> >> David J. >> >>
