Re: UPSERT wiki page, and SQL MERGE syntax - Mailing list pgsql-hackers

From Peter Geoghegan
Subject Re: UPSERT wiki page, and SQL MERGE syntax
Date
Msg-id CAM3SWZSfsEaLUSf-v61_EyyHrbO42eOb6XiZ7s4CTNQ1vNBPnQ@mail.gmail.com
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In response to Re: UPSERT wiki page, and SQL MERGE syntax  (Marti Raudsepp <marti@juffo.org>)
Responses Re: UPSERT wiki page, and SQL MERGE syntax
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On Wed, Oct 8, 2014 at 5:37 PM, Marti Raudsepp <marti@juffo.org> wrote:
> Only in case the trigger changes *key* columns necessary for atomicity
> (i.e. from the WITHIN index). Other columns are fair game. The
> restriction seems justifiable to me: it's unreasonable to be atomic
> with respect to values that change mid-way.

> If you don't see any reasons why it can't be done, these benefits seem
> clear to me. I think the tradeoffs at least warrant wider discussion.

I don't.  That's very surprising. One day, it will fail unexpectedly.
As proposed, the way BEFORE INSERT triggers fire almost forces users
to consider the issues up-front.

Note that the CONFLICTING() behavior with respect to BEFORE INSERT
triggers work's the same as MySQL's "INSERT ON DUPLICATE KEY UPDATE
foo = VALUES(foo)" thing. There was agreement that that was the right
behavior, it seemed.

-- 
Peter Geoghegan



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