Re: INSERT ... ON CONFLICT {UPDATE | IGNORE}

On Thu, Dec 11, 2014 at 1:11 AM, Peter Geoghegan <pg(at)heroku(dot)com> wrote:
> On Mon, Dec 8, 2014 at 8:16 PM, Peter Geoghegan <pg(at)heroku(dot)com> wrote:
>> Attached revision, v1.6, slightly tweaks the ordering of per-statement
>> trigger execution.
>
> Right now, there is no way for a before row insert/update trigger to
> determine whether it was called as part of an INSERT ... ON CONFLICT
> UPDATE or not. It's also not possible for a DO INSTEAD trigger on a
> view (a before row insert trigger) to determine that it was called
> specifically due to an INSERT...IGNORE (which I think ought to imply
> that any corresponding, "redirected" insertion into a table should
> also use IGNORE....that's at least going to be something that a
> certain number of apps will need to be made robust against).
>
> The question is: Do we want to expose this distinction to triggers?
> The natural way to do so would probably be to add TG_SPECULATIVE
> special variable to plpgsql (and equivalent variables in other PLs).
> This text variable would be either "UPSERT" or "IGNORE"; it would be
> NULL when it was not applicable (e.g. with traditional INSERTs).
>
> How do people feel about this? Is it important to include this in our
> initial cut of the feature? I thought that I'd avoid that kind of
> thing until prompted to address it by others, since it probably won't
> end up being a common concern, but I'd like to hear a few opinions.

It's probably something we should add, but there's enough to do
getting the basic feature working first.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
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