Re: Join push-down support for foreign tables

On 2015/03/04 17:31, Kouhei Kaigai wrote:
>> On 2015/03/03 21:34, Shigeru Hanada wrote:
>>> I rebased "join push-down" patch onto Kaigai-san's Custom/Foreign Join
>>> v6 patch.

>> Maybe I'm missing something, but did we agree to take this approach, ie,
>> "join push-down" on top of custom join? There is a comment ahout that
>> [1]. I just thought it'd be better to achieve a consensus before
>> implementing the feature further.

> It is not correct. The join push-down feature is not implemented
> on top of the custom-join feature, however, both of them are 99%
> similar on both of the concept and implementation.
> So, we're working to enhance foreign/custom-join interface together,
> according to Robert's suggestion [3], using postgres_fdw extension
> as a minimum worthwhile example for both of foreign/custom-scan.

OK, thanks for the explanation!

>>> but still the patch
>>> has an issue about joins underlying UPDATE or DELETE. Now I'm working
>>> on fixing this issue.

>> Is that something like "UPDATE foo ... FROM bar ..." where both foo and
>> bar are remote? If so, I think it'd be better to push such an update
>> down to the remote, as discussed in [2], and I'd like to work on that
>> together!

> Hanada-san, could you give us test query to reproduce the problem
> above? I and Fujita-san can help to investigate the problem from
> different standpoints for each.

Yeah, will do.

Best regards,
Etsuro Fujita