The following bug has been logged online:
Bug reference: 5035
Logged by:
Email address: tkarlik@ultimo.pl
PostgreSQL version: 8.3.6
Operating system: Linux
Description: cast 'text' to 'name' doesnt work in plpgsql function
Details:
Comparing 'text' to 'name' in plpgsl function needs explicit casting to
name:
CREATE OR REPLACE FUNCTION table_exists(tblname text) RETURNS boolean AS '
DECLARE
exists boolean;
BEGIN
SELECT 1 INTO exists FROM pg_class WHERE relname = name($1);
RETURN exists;
END;
' LANGUAGE 'plpgsql' IMMUTABLE;
test_db=# select table_exists('test_table');
table_exists
--------------
(1 row)
Time: 0,561 ms
test_db=# select 1 from pg_class where relname = 'test_table';
?column?
----------
(0 rows)
Time: 0,337 ms
Without casting function executes much slower:
CREATE OR REPLACE FUNCTION table_exists(tblname text) RETURNS boolean AS '
DECLARE
exists boolean;
BEGIN
SELECT 1 INTO exists FROM pg_class WHERE relname = name($1);
RETURN exists;
END;
' LANGUAGE 'plpgsql' IMMUTABLE;
test_db=# select table_exists('test_table');
table_exists
--------------
(1 row)
Time: 15,022 ms
Database contains more than 20 000 pg_class tuples.
