On 05/27/2014 11:00 PM, Tom Lane wrote: > Andrew Dunstan <and...@dunslane.net> writes: >> On 05/27/2014 03:57 PM, Heikki Linnakangas wrote: >>> On 05/27/2014 10:53 PM, Andrew Dunstan wrote: >>>> I've been on the receiving end of a couple of mumbles about the fact >>>> that the JSON rendering code ignores casts of builtin types to JSON. >>>> This was originally done as an optimization to avoid doing cache lookups >>>> for casts for things we knew quite well how to turn into JSON values >>>> (unlike, say, hstore). However, there is at least one concrete case >>>> where this has some possibly undesirable consequences, namely >>>> timestamps. Many JSON processors, especially JavaScript/ECMAScript >>>> processors, require timestamp values to be in ISO 8601 format, with a >>>> 'T' between the date part and the time part, and thus they barf on the >>>> output we produce for such values. >>> I don't understand what ignoring casts of builtin types to JSON means. >>> Can you give an example? >> See src/backend/utils/adt/json.c:json_categorize_type() lines 1280-1300. >> When rendering some value as part of a json string, if a cast exists >> from the data type to json, then the cast function is used to render the >> json instead of the type's normal output function, but only if it's not >> a builtin type. > How exactly would disabling that code have any effect on timestamp > rendering? There's no cast to json from timestamps (nor any other > builtin type, except jsonb). I think Andrews idea was, that if cast were used, one could fix the above problem by defining a correct cast.
> > I'd be inclined to think a more useful answer to this issue would be to > make json.c special-case timestamps, as it already does for numerics. > > regards, tom lane But I agree that special-casing the code to use the de-facto json standard of using ISO 8601 date representation is a better solution. Just make sure you get the TZ part right - this is another place where PostgreSQL often differs from other systems' understanding of ISO timestamps. Cheers -- Hannu Krosing PostgreSQL Consultant Performance, Scalability and High Availability 2ndQuadrant Nordic OÜ -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
