Re: [HACKERS] Foreign Join pushdowns not working properly for outer joins

On 13 April 2017 at 11:22, Peter Eisentraut
<peter.eisentraut@2ndquadrant.com> wrote:
> Is this patch considered ready for review as a backpatch candidate?

Yes, however, the v5 patch is based on master. The v4 patch should
apply to 9.6. Diffing the two patches I see another tiny change to a
comment, of which I think needs re-worded anyway.

+ * This function should usually set FDW options in fpinfo after the join is
+ * deemed safe to push down to save some CPU cycles. But We need server
+ * specific options like extensions to decide push-down safety. For
+ * checking extension shippability, we need foreign server as well.
+ */

This might be better written as:

Ordinarily, we might be tempted into delaying the merging of the FDW
options until we've deemed the foreign join to be ok. However, we must
do this before performing this test so that we know which quals can be
evaluated on the foreign server. This may depend on the
shippable_extensions.

Apart from that, it all looks fine to me.

-- David Rowley                   http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training & Services