2009/9/7 Pavel Stehule <pavel.stehule@gmail.com>:
> Hello
>
> 2009/9/7 Tomasz Karlik <Tomasz.Karlik@ultimo.pl>:
>>
>>
>>>>> Alvaro Herrera <alvherre@commandprompt.com> 9/4/2009 7:23 PM >>>
>> tkarlik@ultimo.pl wrote:
>>
>>> Without casting function executes much slower:
>>>
>>> CREATE OR REPLACE FUNCTION table_exists(tblname text) RETURNS boolean A=
S '
>>> DECLARE
>>> exists boolean;
>>> BEGIN
>>>=C2=A0=C2=A0=C2=A0=C2=A0 SELECT 1 INTO exists FROM pg_class WHERE relnam=
e =3D name($1);
>>>=C2=A0=C2=A0=C2=A0=C2=A0 RETURN exists;
>>> END;
>>> ' LANGUAGE 'plpgsql' IMMUTABLE;
>>
>
> it some strange. What version do you use?
>
> on 5.4
sorry 8.4
>
> postgres=3D# explain select * from pg_class where relname=3D'aaa';
> =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 QUERY PL=
AN
>
> -------------------------------------------------------------------------=
-------
> -------------
> =C2=A0Index Scan using pg_class_relname_nsp_index on pg_class =C2=A0(cost=
=3D0.00..8.27 rows=3D
> 1 width=3D185)
> =C2=A0 Index Cond: (relname =3D 'aaa'::name)
> (2 rows)
>
> the casting is implicit.
>
> regards
> Pavel Stehule
>
>> If you're looking for a speedy answer, try a SQL function, not plpgsql.
>>
>>
>> The same issue when using SQL function... However other casting (for exa=
mple
>> int4->int8) works properly.
>>
>
