Re: Bug in ExecModifyTable function and trigger issues for foreign tables

On Mon, May 15, 2017 at 2:46 PM, Ildus Kurbangaliev
<i(dot)kurbangaliev(at)postgrespro(dot)ru> wrote:
> On Mon, 15 May 2017 10:34:58 +0530
> Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
>
>> On Sun, May 14, 2017 at 9:54 PM, Dilip Kumar <dilipbalaut(at)gmail(dot)com>
>> wrote:
>> > After your fix, now tupleid is invalid which is expected, but seems
>> > like we need to do something more. As per the comments seems like it
>> > is expected to get the oldtuple from planSlot. But I don't see any
>> > code for handling that part.
>>
>> Maybe we should do something like attached patch.
>>
>
> Hi,
> planSlot contains already projected tuple, you can't use it as oldtuple.
> I think problem is that `rewriteTargetListUD` called only for parent
> relation, so there is no `wholerow` attribute for foreign tables.

Yes. postgresAddForeignUpdateTargets() which is called by
rewriteTargetListUD injects "ctid". "wholerow" is always there. Not
for postgres_fdw but for other wrappers it might be a bad news. ctid,
whole row obtained from the remote postgres server will fit the tuple
descriptor of parent, but for other FDWs the column injected by
rewriteTargetListUD() may make the child tuple look different from
that of the parent, so we may not pass that column down to the child.

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