Re: Push down more full joins in postgres_fdw

On Mon, Sep 26, 2016 at 4:06 PM, Etsuro Fujita
<fujita(dot)etsuro(at)lab(dot)ntt(dot)co(dot)jp> wrote:
> On 2016/09/26 18:06, Ashutosh Bapat wrote:
>>
>> On Mon, Sep 26, 2016 at 1:05 PM, Etsuro Fujita
>> <fujita(dot)etsuro(at)lab(dot)ntt(dot)co(dot)jp> wrote:
>
>
>>> ISTM that the use of the same RTI for subqueries in multi-levels in a
>>> remote
>>> SQL makes the SQL a bit difficult to read. How about using the position
>>> of
>>> the join rel in join_rel_list, (more precisely, the position plus
>>> list_length(root->parse->rtable)), instead?
>
>
>> We switch to hash table to maintain the join RelOptInfos when the
>> number of joins grows larger, where the position won't make much
>> sense.
>
>
> That's right, but we still store the joinrel into join_rel_list after
> creating that hash table. That hash table is just for fast lookup. See
> build_join_rel.

Sorry, I wasn't clear in my reply. As the list grows, it will take
longer to locate the RelOptInfo of the given join. Doing that for
creating an alias seems an overkill.

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