Re: Change lock requirements for adding a trigger

On Wed, 2008-06-04 at 10:59 -0400, Tom Lane wrote:
> Decibel! <decibel@decibel.org> writes:
> > Ok, I'll take a stab at such a list. Can anyone think of any reasons  
> > why CREATE TRIGGER couldn't get by with ShareLock?
> 
> pg_class.reltriggers.

ISTM that we do this in many ways on pg_class, if we believe the docs.

We have

* relhasindex (bool) set by CREATE INDEX but not unset by DROP INDEX

* relhasrules (bool)

* reltriggers (int2)  set by CREATE and DROP, since its an integer

Seems we should have one consistent way of adding associated objects.

If CREATE INDEX can take a Share lock and can update pg_class, why would
it not be theoretically possible for CREATE TRIGGER? 

-- Simon Riggs           www.2ndQuadrant.comPostgreSQL Training, Services and Support