Re: [HACKERS] Oddity in error handling of constraint violation inExecConstraints for partitioned tables

Hi Amit,

On 2017/07/24 14:09, Amit Khandekar wrote:
>>> On 2017/07/10 14:15, Etsuro Fujita wrote:
>>> Another thing I noticed is the error handling in ExecWithCheckOptions; it
>>> doesn't take any care for partition tables, so the column description in
>>> the error message for WCO_VIEW_CHECK is built using the partition table's
>>> rowtype, not the root table's.  But I think it'd be better to build that
>>> using the root table's rowtype, like ExecConstraints, because that would
>>> make the column description easier to understand since the parent view(s)
>>> (from which WithCheckOptions evaluated there are created) would have been
>>> defined on the root table.  This seems independent from the above issue,
>>> so I created a separate patch, which I'm attaching. What do you think
>>> about that?
> 
> + if (map != NULL)
> + {
> + tuple = do_convert_tuple(tuple, map);
> + ExecStoreTuple(tuple, slot, InvalidBuffer, false);
> + }
> 
> Above, the tuple descriptor also needs to be set, since the parent and
> child partitions can have different column ordering.
> 
> Due to this, the following testcase crashes :
> 
> CREATE TABLE range_parted (a text,b int, c int) partition by range (b);
> CREATE VIEW upview AS SELECT * FROM range_parted WHERE (select c >
> 120) WITH CHECK OPTION;
> create table part_a_1_a_10(b int, c int, a text);
> alter table range_parted attach partition part_a_1_a_10 for values
> from (1) to (10);
> insert into upview values ('a', 2, 100);

Good catch.  Thanks for creating the patch.

There are other places with similar code viz. those in ExecConstraints()
that would need fixing.  Without the same, the following causes a crash
(building on your example):

alter table range_parted add constraint check_c check (c > 120);
insert into range_parted values ('a', 2, 100);
server closed the connection unexpectedly
    This probably means the server terminated abnormally
    before or while processing the request.
The connection to the server was lost. Attempting reset: Failed.

Attached is the updated version of your patch.  A test is also added in
insert.sql on lines of the above example.

Will add this to the PG 10 open items list.

Thanks,
Amit

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