Re: Querying foreign table with SP-GiST index results in “ERROR: cache lookup failed for type 0”

Jeff Janes <jeff.janes@gmail.com>

From: Jeff Janes <jeff.janes@gmail.com>
To: Joao Ferreira <jpgferreira@yahoo.com>
Cc: "pgsql-bugs@lists.postgresql.org" <pgsql-bugs@lists.postgresql.org>
Date: 2019-06-18T12:22:14Z
Lists: pgsql-bugs

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On Tue, Jun 18, 2019 at 8:02 AM Joao Ferreira <jpgferreira@yahoo.com> wrote:

> Greetings,
>
> 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.

Cheers,

Jeff