Re: BUG #18568: BUG: Result wrong when do group by on partition table!

狂奔的蜗牛 <1105066510(at)qq(dot)com> 于2024年8月7日周三 16:06写道：

> PartCollMatchesExprColl() is not strict enough.
> If partcoll == InvalidOid and groupcoll != InvalidOid,
> PartCollMatchesExprColl() return true always.
> Just determine whether groupcoll is equal to partcoll, like this "partcoll
> == groupcoll".
>
> I understand what you said. Actually, I keep it just curious when partcoll
is InvalidOid. Why it works for partition prune.
Is it not same between check partkey is equal to groupexpr and check
partkey is equal to qualclause?

> We cannot delete "if (IsA(groupexpr, RelableTyple) " branch,
> becasuse if groupexpr is RelabelType and partcoll equal to groupcoll,
> the "equal(groupexpr, partexpr) && PartKeyCollMatchesExprColl(partcoll,
> groupexpr_coll)" condition return false!!!
> This is not what we expect.
>

" if groupexpr is RelabelType and partcoll equal to groupcoll ", according
to original logic, will return false in this situation.
Now you think we can support above situation. Am I understand correctly?
We're better to add more test case to cover the code if we're going to
support this. The test cases now seem not going
into the RelableTyple branch.

> We could rename "groupexpr_coll" to groupcoll, it looks more elegant.
>
> No objection. You can continue to support RelableType situation and add
more test cases based on V4.

--
Tender Wang