Re: BUG #5797: Strange bug with hstore

On Sun, Dec 26, 2010 at 12:29 AM, Maxim Boguk <maxim.boguk@gmail.com> wrote:
> On Tue, Dec 21, 2010 at 7:48 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> "Maxim Boguk" <Maxim.Boguk@gmail.com> writes:
>>> Bad explain:
>>> billing=3D# EXPLAIN SELECT * from domains where
>>> name=3D'"name"=3D>"somedomain"'::text::hstore->'name';
>>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0=
 =A0 =A0 =A0 =A0 =A0QUERY PLAN
>>> -----------------------------------------------------------------------=
-----
>>> ------------------------
>>> =A0Seq Scan on domains =A0(cost=3D0.00..7775.91 rows=3D1 width=3D230)
>>> =A0 =A0Filter: ((name)::text =3D (('"name"=3D>"somedomain"'::text)::hst=
ore ->
>>> 'name'::text))
>>> (index not used)
>>
>> The reason for this is that hstore fails to label its I/O functions as
>> immutable (or even stable) in 8.4. =A0This is fixed in 9.0.
>>
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0regards, tom lane
>>
>
> Sorry for late responce and thank you for clarification.
>
> My research of that problem leads me to conclusion that can be fixed
> on 8.4.4 with:
> =A0ALTER FUNCTION hstore_in(cstring) IMMUTABLE;
> but is it really safe?
> Or text->hstore conversion in 8.4 is really VOLATILE as labeled in
> hstrore module?

I think your proposed change is safe.

--=20
Robert Haas
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