>>> Pavel Stehule <[email protected]> 9/7/2009 3:47 PM >>>
Hello
2009/9/7 Tomasz Karlik <[email protected]>:
>
>
>>>> Alvaro Herrera <[email protected]> 9/4/2009 7:23 PM >>>
> [email protected] wrote:
>
>> 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;
>
it some strange. What version do you use?
on 5.4
postgres=# explain select * from pg_class where relname='aaa';
QUERY PLAN
--------------------------------------------------------------------------------
-------------
Index Scan using pg_class_relname_nsp_index on pg_class (cost=0.00..8.27 rows=
1 width=185)
Index Cond: (relname = 'aaa'::name)
(2 rows)
the casting is implicit.
It does'nt work only inside function. Look for execution times in my first
post. Maybe the planner treats SQL SELECT query other than procedural SELECT
INTO?
