SET client_min_messages=NOTICE; \i test-common/disable_jit.include DO $$ BEGIN IF current_setting('server_version_num')::bigint >= 110000 THEN SET jit = off; END IF; END; $$ LANGUAGE plpgsql; CREATE EXTENSION multicorn; CREATE server multicorn_srv foreign data wrapper multicorn options ( wrapper 'multicorn.testfdw.TestForeignDataWrapper' ); CREATE user mapping FOR current_user server multicorn_srv options (usermapping 'test'); -- Test for two thing: first, that when a low total row count, -- a full seq scan is used on a join. CREATE foreign table testmulticorn ( test1 character varying, test2 character varying ) server multicorn_srv options ( option1 'option1' ); explain select * from testmulticorn; NOTICE: [('option1', 'option1'), ('usermapping', 'test')] NOTICE: [('test1', 'character varying'), ('test2', 'character varying')] QUERY PLAN ---------------------------------------------------------------------- Foreign Scan on testmulticorn (cost=10.00..400.00 rows=20 width=20) (1 row) explain select * from testmulticorn m1 inner join testmulticorn m2 on m1.test1 = m2.test1; QUERY PLAN ------------------------------------------------------------------------------------- Nested Loop (cost=20.00..806.05 rows=2 width=128) Join Filter: ((m1.test1)::text = (m2.test1)::text) -> Foreign Scan on testmulticorn m1 (cost=10.00..400.00 rows=20 width=20) -> Materialize (cost=10.00..400.10 rows=20 width=20) -> Foreign Scan on testmulticorn m2 (cost=10.00..400.00 rows=20 width=20) (5 rows) explain select * from testmulticorn m1 left outer join testmulticorn m2 on m1.test1 = m2.test1; QUERY PLAN ------------------------------------------------------------------------------------- Nested Loop Left Join (cost=20.00..806.05 rows=20 width=128) Join Filter: ((m1.test1)::text = (m2.test1)::text) -> Foreign Scan on testmulticorn m1 (cost=10.00..400.00 rows=20 width=20) -> Materialize (cost=10.00..400.10 rows=20 width=20) -> Foreign Scan on testmulticorn m2 (cost=10.00..400.00 rows=20 width=20) (5 rows) DROP foreign table testmulticorn; -- Second, when a total row count is high -- a parameterized path is used on the test1 attribute. CREATE foreign table testmulticorn ( test1 character varying, test2 character varying ) server multicorn_srv options ( option1 'option1', test_type 'planner' ); explain select * from testmulticorn; NOTICE: [('option1', 'option1'), ('test_type', 'planner'), ('usermapping', 'test')] NOTICE: [('test1', 'character varying'), ('test2', 'character varying')] QUERY PLAN ---------------------------------------------------------------------------------- Foreign Scan on testmulticorn (cost=10.00..200000000.00 rows=10000000 width=20) (1 row) explain select * from testmulticorn m1 inner join testmulticorn m2 on m1.test1 = m2.test1; QUERY PLAN ------------------------------------------------------------------------------------------- Nested Loop (cost=20.00..400100000.00 rows=500000000000 width=128) -> Foreign Scan on testmulticorn m1 (cost=10.00..200000000.00 rows=10000000 width=20) -> Foreign Scan on testmulticorn m2 (cost=10.00..20.00 rows=1 width=20) Filter: ((m1.test1)::text = (test1)::text) (4 rows) explain select * from testmulticorn m1 left outer join testmulticorn m2 on m1.test1 = m2.test1; QUERY PLAN ------------------------------------------------------------------------------------------- Nested Loop Left Join (cost=20.00..400100000.00 rows=500000000000 width=128) -> Foreign Scan on testmulticorn m1 (cost=10.00..200000000.00 rows=10000000 width=20) -> Foreign Scan on testmulticorn m2 (cost=10.00..20.00 rows=1 width=20) Filter: ((m1.test1)::text = (test1)::text) (4 rows) DROP USER MAPPING FOR current_user SERVER multicorn_srv; DROP EXTENSION multicorn cascade; NOTICE: drop cascades to 2 other objects DETAIL: drop cascades to server multicorn_srv drop cascades to foreign table testmulticorn