Re: INSERT ... ON CONFLICT UPDATE/IGNORE 4.0 - Mailing list pgsql-hackers

From Geoff Winkless
Subject Re: INSERT ... ON CONFLICT UPDATE/IGNORE 4.0
Date
Msg-id CAEzk6feoR301g57YOmbpVzx+49sTS_2w_Qq2DKzu0u6bKRf4YQ@mail.gmail.com
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In response to Re: INSERT ... ON CONFLICT UPDATE/IGNORE 4.0  (Andres Freund <andres@anarazel.de>)
List pgsql-hackers
On 8 May 2015 at 16:51, Andres Freund <andres@anarazel.de> wrote:
On 2015-05-08 16:36:07 +0100, Geoff Winkless wrote:
> I thought the previous version suggested multiple possible targets and
> actions, this suggests that while there can be multiple targets the
> action is always the same.

I don't think any version of the patch included that functionality. I
can see it being useful, but it'd make a bunch of things more
complicated, so I doubt we'll get there for 9.5.

​I'm not particularly bothered by it - I only see it ever being useful on the extreme edge case, and 
I certainly wouldn't want
​it 
to hold up the release
 - but it was the only reason I could see for requiring a target_clause in the first place (I
​expect that's why I 
misread the docs previously!). If you can't specify different actions based on the target_clause, what's the point in forcing the user to enumerate it?

> example (or similar); do we think people will be smart enough to realise
> that's possible without one?​

Hm. I'm tempted to say that the synopis makes that clear enough. 

​Unless I'm missing it, it's really only in "This happens on a row-by-row basis" and in the "deterministic" paragraph that you even mention multi-line inserts in the ON CONFLICT section.​
​​
I
​ ​
personally never check such examples though, so maybe I'm the wrong
person to judge.

​I'm afraid I'm the sort of person who goes straight to the examples :)

Maybe I'll just suggest then that there's a _potential for confusion_ if you only give examples of the first kind - people might place some inference on the fact that the examples only show single-row INSERTs.

Geoff

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