Re: [HACKERS] generated columns
| От | Pavel Stehule |
|---|---|
| Тема | Re: [HACKERS] generated columns |
| Дата | |
| Msg-id | CAFj8pRB=L3At5R=DXWRw7OFCdaeZ_+3S5e==DbGgD_7POsqngA@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: [HACKERS] generated columns (Peter Eisentraut <peter.eisentraut@2ndquadrant.com>) |
| Ответы |
Re: [HACKERS] generated columns
|
| Список | pgsql-hackers |
ne 13. 1. 2019 v 10:43 odesílatel Peter Eisentraut <peter.eisentraut@2ndquadrant.com> napsal:
On 11/01/2019 16:22, Pavel Stehule wrote:
> The documentation contains paragraph
>
> + The generation expression can only use immutable functions and cannot
> + use subqueries or reference anything other than the current row
> in any
> + way.
>
> It is necessary for stored columns?
See here:
https://www.postgresql.org/message-id/b5c27634-1d44-feba-7494-ce5a31f914ca@2ndquadrant.com
I understand - it is logical. But it is sad, so this feature is not complete. The benefit is not too big - against functional indexes or views. But it can be first step.
> I tested it with pseudo constant - current_timestamp, session_user. But
> current_database() is disallowed.
>
> on second hand, this is strange
>
> postgres=# create table foo3 (inserted text generated always as
> (current_timestamp) virtual);
> CREATE TABLE
Ah, the volatility checking needs some improvements. I'll address that
in the next patch version.
ok
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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