Re: Push down more full joins in postgres_fdw

On 2016/09/26 20:20, Ashutosh Bapat wrote:
> 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.

> 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.

The join rel is appended to the end of the list, so I was thinking to
get the position info by list_length during postgresGetForeignJoinPaths.

Best regards,
Etsuro Fujita