Re: Cache lookup error when using jsonb, json_build_object and a WITH clause

Hi,

On 2014-05-09 21:40:07 +0900, Michael Paquier wrote:
> Hi all,
>
> I found the following error when playing with jsonb and json_build_object:
> =# with jsonb_data as (select * from jsonb_each('{"aa" :
> "po"}'::jsonb)) select json_build_object(key,value) from jsonb_data;
> ERROR: XX000: cache lookup failed for type 2147483650
> LOCATION: lookup_type_cache, typcache.c:193
>
> I would have expected the result to be the same as in the case of json:
> =# with json_data as (select * from json_each('{"aa" : "po"}'::json))
> select json_build_object(key,value) from json_data;
> json_build_object
> -------------------
> {"aa" : "po"}
> (1 row)

Whoa. There's two wierd things here:
a) "jsonb" has a typcategory 'C'. Marking a composite type. "json" has
'U'.

b) datum_to_json() thinks it's a good idea to use typcategory to decide
how a type is output. Isn't that pertty fundamentally flawed? To
detect composite types it really should look at typtype, now?

Greetings,

Andres Freund

--
Andres Freund http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services