Re: [PATCH] Generalized JSON output functions
| От | Shulgin, Oleksandr |
|---|---|
| Тема | Re: [PATCH] Generalized JSON output functions |
| Дата | |
| Msg-id | CACACo5QNMBfOM3XSZfObExk=PMH4=Q2+4__=AGN-ct9AWeskDA@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: [PATCH] Generalized JSON output functions (Pavel Stehule <pavel.stehule@gmail.com>) |
| Ответы |
Re: [PATCH] Generalized JSON output functions
|
| Список | pgsql-hackers |
On Fri, Jul 10, 2015 at 4:04 PM, Pavel Stehule <pavel.stehule@gmail.com> wrote:
instead2. why you did indirect call via JsonOutContext?What is benefit
dst.value(&dst, (Datum) 0, JSONTYPE_NULL, InvalidOid, InvalidOid, false);
json_out_value(&dst, ....)For consistency. Even though we initialize the output context ourselves, there might be some code introduced between json_out_init_context() and dst.value() calls that replaces some of the callbacks, and then there would be a difference.with this consistency? I didn't see this style everywhere in Postgres? Isn't it premature optimization?
Well, one could call it premature pessimization due to dynamic call overhead.
IMO, the fact that json_out_init_context() sets the value callback to json_out_value is an implementation detail, the other parts of code should not rely on. And for the Explain output, there definitely going to be *some* code between context initialization and output callbacks: these are done in a number of different functions.
--
Alex
В списке pgsql-hackers по дате отправления: