Re: GSoC 2017: Foreign Key Arrays

On Tue, 18 Jul 2017 at 7:43 pm, Alexander Korotkov <aekorotkov(at)gmail(dot)com>
wrote:

> On T upue, Jul 18, 2017 at 2:24 AM, Mark Rofail <markm(dot)rofail(at)gmail(dot)com>
> wrote:
>
>> On Wed, Jul 12, 2017 at 12:53 AM, Alvaro Herrera <
>> alvherre(at)2ndquadrant(dot)com> wrote:
>>>
>>> We have one opclass for each type combination -- int4 to int2, int4 to
>>> int4, int4 to int8, etc. You just need to add the new strategy to all
>>> the opclasses.
>>
>>
>> I tried this approach by manually declaring the operator multiple of
>> times in pg_amop.h (src/include/catalog/pg_amop.h)
>>
>> so instead of the polymorphic declaration
>> DATA(insert ( 2745 2277 2283 5 s 6108 2742 0 )); /* anyarray @>>
>> anyelem */
>>
>> multiple declarations were used, for example for int4[] :
>> DATA(insert ( 2745 1007 20 5 s 6108 2742 0 )); /* int4[] @>> int8 */
>> DATA(insert ( 2745 1007 23 5 s 6108 2742 0 )); /* int4[] @>> int4 */
>> DATA(insert ( 2745 1007 21 5 s 6108 2742 0 )); /* int4[] @>> int2 */
>> DATA(insert ( 2745 1007 1700 5 s 6108 2742 0 ));/* int4[] @>> numeric
>> */
>>
>> However, make check produced:
>> could not create unique index "pg_amop_opr_fam_index"
>> Key (amopopr, amoppurpose, amopfamily)=(6108, s, 2745) is duplicated.
>>
>> Am I implementing this the wrong way or do we need to look for another
>> approach?
>>
>
> The problem is that you need to have not only opclass entries for the
> operators, but also operators themselves. I.e. separate operators for
> int4[] @>> int8, int4[] @>> int4, int4[] @>> int2, int4[] @>> numeric. You
> tried to add multiple pg_amop rows for single operator and consequently get
> unique index violation.
>
> Alvaro, do you think we need to define all these operators? I'm not
> sure. If even we need it, I think
> ------
> Alexander Korotkov
> Postgres Professional: http://www.postgrespro.com
> The Russian Postgres Company
>