Re: try_relation_open and relation_open behave different.
| От | Xing GUO |
|---|---|
| Тема | Re: try_relation_open and relation_open behave different. |
| Дата | |
| Msg-id | CACpMh+D5iSQ+-mHJrXCJDZ+KZ3zBTeTZsgP4eRnZJA7Kk=LEGw@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: try_relation_open and relation_open behave different. (Michael Paquier <michael@paquier.xyz>) |
| Ответы |
Re: try_relation_open and relation_open behave different.
|
| Список | pgsql-hackers |
On Mon, Oct 18, 2021 at 2:45 PM Michael Paquier <michael@paquier.xyz> wrote:
On Mon, Oct 18, 2021 at 01:56:07PM +0800, Xing GUO wrote:
> My question is, is it a deliberate design that makes try_relation_open and
> relation_open different? Shall we mention it in the comment of
> try_relation_open OR adding the checker to relation_open?
I am not sure what you mean here, both functions are include comments
to explain their differences, so..
The comments in try_relation_open says:
```
/* ----------------
* try_relation_open - open any relation by relation OID
*
* Same as relation_open, except return NULL instead of failing
* if the relation does not exist.
* ----------------
*/
* try_relation_open - open any relation by relation OID
*
* Same as relation_open, except return NULL instead of failing
* if the relation does not exist.
* ----------------
*/
```
However, I can open an "uncommitted" relation using relation_open() and cannot open it using try_relation_open().
Since Postgres doesn't write the "uncommitted" relation descriptor to SysCache and try_relation_open() checks if the
relation exists in SysCache while relation_open() doesn't check it.
--
Michael
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