On 2017/03/06 11:05, David Rowley wrote:
I've been asked to investigate a case of a foreign join not occurring
on the foreign server as would have been expected.


The attached patch, based on 9.6,  fixes the problem by properly
processing the foreign server options in
postgresGetForeignJoinPaths().

I ended up shifting the code which does this into functions to allow
it to be reused. I also ended up shifting out the code which processes
the table options so that it is consistent.

Reviews from people a bit closer to the foreign join pushdown code are welcome.

Thanks for working on this!

I think the fix would work well, but another way I think is much simpler and more consistent with the existing code is to (1) move code for getting the server info from the outer's fpinfo before calling is_foreign_expr() in foreign_join_ok() and (2) add code for getting the shippable extensions info from the outer's fpinfo before calling that function, like the attached.

Best regards,
Etsuro Fujita

Attachment: foreign_outerjoin_pushdown_fix_efujita.patch
Description: binary/octet-stream

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