Re: [BUG] Fix DETACH with FK pointing to a partitioned table fails

Alvaro Herrera <alvherre@alvh.no-ip.org> 于2024年8月8日周四 06:50写道：

> On 2024-Jul-26, Tender Wang wrote:
>
> > Junwang Zhao <zhjwpku@gmail.com> 于2024年7月26日周五 14:57写道：
> >
> > > There is a bug report[0] Tender comments might be the same issue as
> > > this one, but I tried Alvaro's and mine patch, neither could solve
> > > that problem, I did not tried Tender's earlier patch thought. I post
> > > the test script below in case you are interested.
> >
> > My earlier patch should handle Alexander reported case. But I did not
> > do more test. I'm not sure that wether or not has dismatching between
> > pg_constraint and pg_trigger.
> >
> > I aggred with Alvaro said that "requires a much more invasive
> > solution".
>
> Here's the patch which, as far as I can tell, fixes all the reported
> problems (other than the one in bug 18541, for which I proposed an
> unrelated fix in that thread[1]).  If you can double-check, I would very
> much appreciate that.  Also, I think the test cases the patch adds
> reflect the provided examples sufficiently, but if we're still failing
> to cover some, please let me know.
>

When I review Jehan-Guillaume v2 patch, I found the below codes that need
a little tweak. In DetachPartitionFinalize()
/*
* If the referenced side is partitioned (which we know because our
* parent's constraint points to a different relation than ours) then
* we must, in addition to the above, create pg_constraint rows that
* point to each partition, each with its own action triggers.
*/
if (parentConForm->conrelid != conform->conrelid)

I found that the above IF was always true,  regardless of whether the
referenced side is partitioned.
Although find_all_inheritors() can return an empty children list when the
referenced side is not partitioned,
we can avoid much useless work.
How about this way:
if (get_rel_relkind(conform->confrelid) == RELKIND_PARTITIONED_TABLE)


--
Thanks,
Tender Wang