diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out index b09dce63f5f..60c7e115d61 100644 --- a/contrib/postgres_fdw/expected/postgres_fdw.out +++ b/contrib/postgres_fdw/expected/postgres_fdw.out @@ -613,6 +613,24 @@ SELECT t1."C 1", t2.c1, t3.c1 FROM "S 1"."T 1" t1 full join ft1 t2 full join ft2 RESET enable_hashjoin; RESET enable_nestloop; +-- Test executing assertion in estimate_path_cost_size() that makes sure that +-- retrieved_rows for foreign rel re-used to cost pre-sorted foreign paths is +-- a sensible value even when the rel has tuples=0 +CREATE TABLE loct_empty (c1 int NOT NULL, c2 text); +CREATE FOREIGN TABLE ft_empty (c1 int NOT NULL, c2 text) + SERVER loopback OPTIONS (table_name 'loct_empty'); +INSERT INTO loct_empty + SELECT id, 'AAA' || to_char(id, 'FM000') FROM generate_series(1, 100) id; +DELETE FROM loct_empty; +ANALYZE ft_empty; +EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM ft_empty ORDER BY c1; + QUERY PLAN +------------------------------------------------------------------------------- + Foreign Scan on public.ft_empty + Output: c1, c2 + Remote SQL: SELECT c1, c2 FROM public.loct_empty ORDER BY c1 ASC NULLS LAST +(3 rows) + -- =================================================================== -- WHERE with remotely-executable conditions -- =================================================================== diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c index 2ce42ce3f11..0e977066a8f 100644 --- a/contrib/postgres_fdw/postgres_fdw.c +++ b/contrib/postgres_fdw/postgres_fdw.c @@ -2923,7 +2923,7 @@ estimate_path_cost_size(PlannerInfo *root, */ if (fpinfo->rel_startup_cost >= 0 && fpinfo->rel_total_cost >= 0) { - Assert(fpinfo->retrieved_rows >= 1); + Assert(fpinfo->retrieved_rows >= 0); rows = fpinfo->rows; retrieved_rows = fpinfo->retrieved_rows; diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql index 319c15d635c..151f4f18341 100644 --- a/contrib/postgres_fdw/sql/postgres_fdw.sql +++ b/contrib/postgres_fdw/sql/postgres_fdw.sql @@ -309,6 +309,18 @@ SELECT t1."C 1", t2.c1, t3.c1 FROM "S 1"."T 1" t1 full join ft1 t2 full join ft2 RESET enable_hashjoin; RESET enable_nestloop; +-- Test executing assertion in estimate_path_cost_size() that makes sure that +-- retrieved_rows for foreign rel re-used to cost pre-sorted foreign paths is +-- a sensible value even when the rel has tuples=0 +CREATE TABLE loct_empty (c1 int NOT NULL, c2 text); +CREATE FOREIGN TABLE ft_empty (c1 int NOT NULL, c2 text) + SERVER loopback OPTIONS (table_name 'loct_empty'); +INSERT INTO loct_empty + SELECT id, 'AAA' || to_char(id, 'FM000') FROM generate_series(1, 100) id; +DELETE FROM loct_empty; +ANALYZE ft_empty; +EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM ft_empty ORDER BY c1; + -- =================================================================== -- WHERE with remotely-executable conditions -- ===================================================================