From: 德哥 <digoal@126.com>
To: David G. Johnston <david.g.johnston@gmail.com>
Cc: pgsql-bugs@lists.postgresql.org <pgsql-bugs@lists.postgresql.org>
Subject: Re:Re: BUG #17036: generated column cann't modifyed auto when update
Date: Thu, 27 May 2021 10:47:59 +0800 (CST)
Message-ID: <2e46e6b5.1930.179abb8b6c0.Coremail.digoal@126.com> (raw)
In-Reply-To: <CAKFQuwbkoz3zmL_bEC2ndSX5G9_3xm_+AL2fd+3OTFFH0VePow@mail.gmail.com>
References: <17036-e4d41f4221873a17@postgresql.org>
<CAKFQuwarr8b2=2j2J4GuSV-FwqAXq38ebFR_wTUY=Lg9_YLCJg@mail.gmail.com>
<23824c32.12e8.179ab97fa8a.Coremail.digoal@126.com>
<CAKFQuwbkoz3zmL_bEC2ndSX5G9_3xm_+AL2fd+3OTFFH0VePow@mail.gmail.com>
The generated column can be used to automatically generate the modified timestamp of a tuple, but PG 12 currently supports this scenario. PG 13 has started to change its behavior, which makes our application need to be modified. This is the first time I have ever seen a PG upgrade kill a nice feature.
--
公益是一辈子的事,I'm Digoal,Just Do It.
在 2021-05-27 10:33:40，"David G. Johnston" <david.g.johnston@gmail.com> 写道：
On Wednesday, May 26, 2021, 德哥 <digoal@126.com> wrote:
And immutable function is stable when parameter not change, when parameter changed , the immutable function will recall and recompute.
but in PG 13 and PG 14 , it is also wrong.
```
create or replace function im_now (anyelement) returns timestamptz as $$
select now();
$$ language sql strict immutable;
create table t1 (id int primary key, c1 int, info text, crt_time timestamp,
mod_time timestamp GENERATED ALWAYS AS (im_now(t1)) stored);
This seems to be related to this already reported bug (the similar one I noted in my other reply).
https://www.postgresql.org/message-id/CAM_DEiWR2DPT6U4xb-Ehigozzd3n3G37ZB1%2B867zbsEVtYoJww%40mail.g...
David J.
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To: pgsql-bugs@postgresql.org
Cc: digoal@126.com, david.g.johnston@gmail.com, pgsql-bugs@lists.postgresql.org
Subject: Re:Re: BUG #17036: generated column cann't modifyed auto when update
In-Reply-To: <2e46e6b5.1930.179abb8b6c0.Coremail.digoal@126.com>
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