Re: [HACKERS] how to correctly invalidate a constraint?

Pavel Stehule wrote:
> Hi
> 
> I would to do import without RI check - so I disable RI triggers.
> 
> I would to invalidate constraint on Foreign Keys and then I would to use
> ALTER TABLE VALIDATE CONSTRAINT ...
> 
> I didn't find how to invalidate constraint without direct update
> pg_constraint.
> 
> Is there some clean way?

I think what you want is:
- set the constraint as "not valid", so that the following is a valid operation
- set the RI trigger not to fire, to improve performance of bulk loads
- do the load
- activate the trigger
- validate the constraint

We have SQL commands for everything except the first step.  Now my
question would be: do we want to support that operation as a stand-alone
thing so that you can construct the above from pieces, or do we want
some higher-level command so that the above is less cumbersome?  The
main issue I see is that a single constraint involves several triggers,
and the triggers have internally-derived, very ugly names.  So in my
mind the right way to provide this functionality is to have a command
that operates on the RI constraint and modifies the triggers status.

ALTER TABLE .. ALTER CONSTRAINT [name / ALL] DEACTIVATE  -- sets constraint as NOT VALID, also sets triggers inactive

[user bulkload occurs here]

ALTER TABLE .. ALTER CONSTRAINT [name / ALL] ACTIVATE  -- activates triggers, validates constraint

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
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