Files
postgresql/src/test/regress/sql/expressions.sql
Tom Lane 1acf345869 Ensure casting to typmod -1 generates a RelabelType.
Fix the code changed by commit 5c056b0c2 so that we always generate
RelabelType, not something else, for a cast to unspecified typmod.
Otherwise planner optimizations might not happen.

It appears we missed this point because the previous experiments were
done on type numeric: the parser undesirably generates a call on the
numeric() length-coercion function, but then numeric_support()
optimizes that down to a RelabelType, so that everything seems fine.
It misbehaves for types that have a non-optimized length coercion
function, such as bpchar.

Per report from John Naylor.  Back-patch to all supported branches,
as the previous patch eventually was.  Unfortunately, that no longer
includes 9.6 ... we really shouldn't put this type of change into a
nearly-EOL branch.

Discussion: https://postgr.es/m/CAFBsxsEfbFHEkouc+FSj+3K1sHipLPbEC67L0SAe-9-da8QtYg@mail.gmail.com
2021-12-16 15:36:02 -05:00

73 lines
1.7 KiB
PL/PgSQL

--
-- expression evaluated tests that don't fit into a more specific file
--
--
-- Tests for SQLVAlueFunction
--
-- current_date (always matches because of transactional behaviour)
SELECT date(now())::text = current_date::text;
-- current_time / localtime
SELECT now()::timetz::text = current_time::text;
SELECT now()::time::text = localtime::text;
-- current_timestamp / localtimestamp (always matches because of transactional behaviour)
SELECT current_timestamp = NOW();
-- precision
SELECT length(current_timestamp::text) >= length(current_timestamp(0)::text);
-- localtimestamp
SELECT now()::timestamp::text = localtimestamp::text;
-- current_role/user/user is tested in rolnames.sql
-- current database / catalog
SELECT current_catalog = current_database();
-- current_schema
SELECT current_schema;
SET search_path = 'notme';
SELECT current_schema;
SET search_path = 'pg_catalog';
SELECT current_schema;
RESET search_path;
--
-- Test parsing of a no-op cast to a type with unspecified typmod
--
begin;
create table numeric_tbl (f1 numeric(18,3), f2 numeric);
create view numeric_view as
select
f1, f1::numeric(16,4) as f1164, f1::numeric as f1n,
f2, f2::numeric(16,4) as f2164, f2::numeric as f2n
from numeric_tbl;
\d+ numeric_view
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;