Re: What is the extent of FDW join pushdown support in 9.5?

On 9/15/15 10:02 PM, Kouhei Kaigai wrote:
>> The 9.5 release notes contain this promising but cryptic item:
>>
>> - Allow foreign data wrappers and custom scans to implement join
>> pushdown (KaiGai Kohei)
>>
>> As phrased, this seems to mean, "it can be done, but we haven't done
>> it". But there is no link to any documentation that explains how to do
>> this. The commit that appears to have added this feature touches
>> postgres_fdw, but neither the documentation nor the tests show anything
>> about this feature, and I haven't been able to reproduce anything that
>> would seem to indicate anything like this is at work.
>>
>> So what is the actual extent of this feature?
>>
> It says these enhancement on interface allows extensions to implement
> join operation in their own way (including remote join in case of FDW),
> however, enhancement of postgres_fdw is not yet upstreamed.

Thank you for this clarification. I suppose this item is correct as
written.