diff --git a/src/backend/parser/parse_coerce.c b/src/backend/parser/parse_coerce.c index 12acffcdef..c759d44c4b 100644 --- a/src/backend/parser/parse_coerce.c +++ b/src/backend/parser/parse_coerce.c @@ -760,7 +760,15 @@ coerce_type_typmod(Node *node, Oid targetTypeId, int32 targetTypMod, if (hideInputCoercion) hide_coercion_node(node); - pathtype = find_typmod_coercion_function(targetTypeId, &funcId); + /* + * A negative typmod means that no actual coercion is needed, but we still + * want a RelabelType to ensure that the expression exposes the intended + * typmod. + */ + if (targetTypMod < 0) + pathtype = COERCION_PATH_NONE; + else + pathtype = find_typmod_coercion_function(targetTypeId, &funcId); if (pathtype != COERCION_PATH_NONE) { diff --git a/src/test/regress/expected/expressions.out b/src/test/regress/expected/expressions.out index 4ca89ae559..726c1198a9 100644 --- a/src/test/regress/expected/expressions.out +++ b/src/test/regress/expected/expressions.out @@ -111,4 +111,40 @@ explain (verbose, costs off) select * from numeric_view; Output: numeric_tbl.f1, (numeric_tbl.f1)::numeric(16,4), (numeric_tbl.f1)::numeric, numeric_tbl.f2, (numeric_tbl.f2)::numeric(16,4), numeric_tbl.f2 (2 rows) +-- bpchar, lacking planner support for its length coercion function, +-- could behave differently +create table bpchar_tbl (f1 character(16) unique, f2 bpchar); +create view bpchar_view as + select + f1, f1::character(14) as f114, f1::bpchar as f1n, + f2, f2::character(14) as f214, f2::bpchar as f2n + from bpchar_tbl; +\d+ bpchar_view + View "public.bpchar_view" + Column | Type | Collation | Nullable | Default | Storage | Description +--------+---------------+-----------+----------+---------+----------+------------- + f1 | character(16) | | | | extended | + f114 | character(14) | | | | extended | + f1n | bpchar | | | | extended | + f2 | bpchar | | | | extended | + f214 | character(14) | | | | extended | + f2n | bpchar | | | | extended | +View definition: + SELECT bpchar_tbl.f1, + bpchar_tbl.f1::character(14) AS f114, + bpchar_tbl.f1::bpchar AS f1n, + bpchar_tbl.f2, + bpchar_tbl.f2::character(14) AS f214, + bpchar_tbl.f2 AS f2n + FROM bpchar_tbl; + +explain (verbose, costs off) select * from bpchar_view + where f1::bpchar = 'foo'; + QUERY PLAN +------------------------------------------------------------------------------------------------------------------------------------------------ + Index Scan using bpchar_tbl_f1_key on public.bpchar_tbl + Output: bpchar_tbl.f1, (bpchar_tbl.f1)::character(14), (bpchar_tbl.f1)::bpchar, bpchar_tbl.f2, (bpchar_tbl.f2)::character(14), bpchar_tbl.f2 + Index Cond: ((bpchar_tbl.f1)::bpchar = 'foo'::bpchar) +(3 rows) + rollback; diff --git a/src/test/regress/sql/expressions.sql b/src/test/regress/sql/expressions.sql index 0c57531ec1..74189ad1fd 100644 --- a/src/test/regress/sql/expressions.sql +++ b/src/test/regress/sql/expressions.sql @@ -53,4 +53,20 @@ create view numeric_view as explain (verbose, costs off) select * from numeric_view; +-- bpchar, lacking planner support for its length coercion function, +-- could behave differently + +create table bpchar_tbl (f1 character(16) unique, f2 bpchar); + +create view bpchar_view as + select + f1, f1::character(14) as f114, f1::bpchar as f1n, + f2, f2::character(14) as f214, f2::bpchar as f2n + from bpchar_tbl; + +\d+ bpchar_view + +explain (verbose, costs off) select * from bpchar_view + where f1::bpchar = 'foo'; + rollback;