Re: event triggers with args? - Mailing list pgsql-hackers

From Fabien COELHO
Subject Re: event triggers with args?
Date
Msg-id alpine.DEB.2.10.1502251516420.10787@sto
Whole thread Raw
In response to Re: event triggers with args?  (Andres Freund <andres@2ndquadrant.com>)
List pgsql-hackers
Hello Andres,

>> So I have a question: is there a particular reason why arguments were not
>> provided in the first place?
>
> Yea. The existing trigger argument mechanims is extremely odd
> implementation wise - they don't have real datatypes and aren't passed
> via the normal parameter passing mechanism.

Indeed, I can only agree!

> IIRC we discussed this back when it was introduced and decided against 
> introducing for now.
>
> I think the whole trigger argument infrastructure, even for normal 
> triggers, should be rewritten. After that we could think of adding it 
> for event triggers.

Ok. That sound reasonable. Thanks for the answer.

I think that the new method will have to be upward compatible. This 
suggest providing TG_ARGV with casted to text arguments. Not necessarily a 
big issue.

I've looked into the parser. ISTM that trigger call parameter list could 
use a "expr_list", which would have to be evaluated and serialised in 
pg_trigger, maybe as ROW does.

-- 
Fabien.



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