On Mon, Jan 15, 2018 at 12:31 PM, Tom Lane <t...@sss.pgh.pa.us> wrote:
>> After some thought, it seems that there's a much simpler way that we >> could fix the problem you identified in that original email: if the >> EPQ path isn't properly sorted, have postgres_fdw's >> add_paths_with_pathkeys_for_rel stick a Sort node on top of it. I >> tried this and it does indeed fix Jeff Janes' initial test case. > > Hm. Simple is certainly good, but if there's multiple rows coming > back during an EPQ recheck then I think we have a performance problem. You are correct ... I was wrong about that part, and said so in an email on this thread sent about 45 minutes before yours. However, I still think the patch is a good fix for the immediate issue, unless you see some problem with it. It's simple and back-patchable and does not preclude further work anybody, including you, might want to do in the future. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company
