Re: JSON for PG 9.2

On Sun, Dec 18, 2011 at 11:21 AM, Andrew Dunstan <andrew@dunslane.net> wrote:
>
>
> On 12/18/2011 12:17 PM, Merlin Moncure wrote:
>>
>> One small note about the json type being an extension -- this probably
>> means the json type oid won't be fixed -- not a huge deal but it could
>> affect some corner cases with binary format consumers.
>
> Why would that matter more for JSON than for any other non-core type?

well, it's a minor headache for all the oid-isn't-in-pgtypes.h types,
and only then for high traffic types (which presumably json will be).a while back we coded up a reworked dblink that
wasvariadic and
 
could optionally transfer data between database with the binary wire
format.   any container of a user defined (by oid) type had to be sent
strictly as text which is a big performance hit for certain types.
recent postgres has an undocumented facility to force type oids to a
particular value, but the type definition being inside the create
extension script makes this problematic.

this is a pretty far out objection though, and I could certainly work
around the problem if necessary, but there is some dependency on
pg_types.h in the wild.

merlin