Re: dblink: add polymorphic functions.

On Wed, Jul 29, 2015 at 12:53 PM, Joe Conway <mail@joeconway.com> wrote:
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> On 07/29/2015 09:40 AM, Corey Huinker wrote:
>> Say I've got a table my_partitioned_table (key1 integer, key2
>> integer, metric1 integer, metric2 integer);
>>
>> And I've got many partitions on that table. My code lets you do
>> something like this:
>>
>> select key1, key2, sum(metric1) as a_sum_of_sums, sum(metric2) as
>> another_sum_of_sums from
>> execute_buncha_queries(null::my_partitioned_table,
>> 'connection_string_thats_just_a_loopback', array['select key1,
>> key2, sum(metric1), sum(metric2) from my_partition_p1 group by
>> 1,2', 'select key1, key2, sum(metric1), sum(metric2) from
>> my_partition_p2 group by 1,2', ...]) group by 1,2
>
>> I can't put a cast around execute_buncha_queries because the
>> function won't know how to cast the results coming back from
>> dblink.
>
> Ok, gotcha. So Tom's nearby comment about allowing the
> "p_rowtype%TYPE" syntax to be used in the CAST is spot on (as usual).
> In other words, to get a complete solution for you we would need to
> make both things work, so you could do this inside plpgsql:
>
>   select * from cast(dblink(connstr, sql) as p_rowtype%TYPE);

Would this be a pl/pgsql only solution?

merlin