Re: ALTER TABLE ... NOREWRITE option

On 2012-12-05 22:41:21 +0000, Simon Riggs wrote:
> On 5 December 2012 22:21, Dimitri Fontaine <dimitri(at)2ndquadrant(dot)fr> wrote:
> > Simon Riggs <simon(at)2ndQuadrant(dot)com> writes:
> >>> CREATE EVENT TRIGGER my_event_trigger
> >>> ON table_rewrite
> >>> EXECUTE PROCEDURE consider_whether_to_throw_an_error();
> >>
> >> +1, I was just thinking that myself.
> >
> > +1, and I think that can happen for 9.3, as soon as we agree on the list
> > of code points where we want that event to fire. ALTER TABLE variants
> > that are rewriting the heap, sure. CLUSTER? VACUUM FULL? TRUNCATE?
>
> Events needed
> * Table rewrite
> * Index rebuild

Those should be fairly easy.

> * Relation scan (index/table/toast etc)
> * AccessExclusiveLock

I am worried about the overhead of looking for triggers for those two
though. Especially for RelationScans.

Greetings,

Andres Freund

--
Andres Freund http://www.2ndQuadrant.com/
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