Re: postgres_fdw join pushdown (was Re: Custom/Foreign-Join-APIs)

On Wed, Dec 2, 2015 at 6:45 AM, Ashutosh Bapat
<ashutosh.bapat@enterprisedb.com> wrote:
> It's been a long time since last patch on this thread was posted. I have
> started
> to work on supporting join pushdown for postgres_fdw. Attached please find
> three
> patches
> 1. pg_fdw_core.patch: changes in core related to user mapping handling, GUC
>                       enable_foreignjoin
> 2. pg_fdw_join.patch: postgres_fdw changes for supporting join pushdown

It seems useful to break things up this way.  However, I'm not sure we
want an enable_foreignjoin GUC; in fact, I think we probably don't.
If we want to have a way to control this, postgres_fdw can provide a
custom GUC or FDW option for that.

And to be honest, I haven't really been able to understand why join
pushdown needs changes to user mapping handling.  Just hypothetically
speaking, if I put my foot down and said we're not committing any of
that stuff, how and why would that impact our ability to have join
pushdown in 9.6?

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company