Re: Remove mention in docs that foreign keys on partitioned tables are not supported

On Thu, Jun 7, 2018 at 7:51 AM, Amit Langote
<Langote_Amit_f8(at)lab(dot)ntt(dot)co(dot)jp> wrote:
> On 2018/06/06 20:51, Ashutosh Bapat wrote:
>> The existing wording suggests that the user
>> creates the triggers on the partitioned table, and that will be
>> supported always, which can lead to problems.
>
> Do you mean the following wording
>
> "BEFORE ROW triggers, if necessary, must be defined on individual
> partitions, not the partitioned table."
>
> suggests that user *can* create triggers on the partitioned table? I
> guess I can see how one may read it that way. How about we make it say
> something like:
>
> "BEFORE ROW triggers are not supported on partitioned tables; a user can
> still define them, if necessary, on individual partitions though."

Whichever way said, I am reading it like "We don't support BEFORE ROW
triggers on partitioned tables, but you can have them by creating
those on partitions". That is going to be a trouble for us.

>
>> With this description,
>> if the user finds out that BEFORE triggers are supported on partitions
>> and creates those, and we implement something to support those on
>> partitioned table, s/he will have to change the implementation
>> accordingly.
>
> So you mean that the existing wording *encourages* users to use the
> feature to create BR triggers on individual partitions whereas it
> shouldn't,

right.

> that is, users can find out about that feature by themselves by
> trying it out?

I didn't understand that part.

Probably we just say that BEFORE ROW triggers are not supported on a
partitioned table. It's good enough not to suggest it ourselves. If
users find out that they can create triggers on partitions and use it
that way, they may or may not have to change their implementation
later when we start supporting those. But then we didn't suggest that
they do it that way.

--
Best Wishes,
Ashutosh Bapat
EnterpriseDB Corporation
The Postgres Database Company