I'm using PostgreSQL 11.3 and I want to access a table in another Postgres database using postgres_fdw but since the original table has an SP-GiST index on a geometry column, the query on the foreign table fails with "ERROR: cache lookup failed for type 0", even if the table is empty (Step 7). This doesn't happen if the query is done directly to the remote table (Steps 3 and 6) or if the remote table doesn't have the index (Steps 3 and 4).
I've verified this on ubuntu 18.04 with 11.3 installed from PGDG apt repo, and attached a single-file reproduction.
If I change from sp-gist to just gist, there is no problem. And if I change to indexing a built-in sp-gist operator class (point rather than geom), there is also no problem.
Getting postgis to compile is a bit hard and slow, so I haven't completed any tests against the unreleased versions yet.
