Re: [GSoC2014] Patch ALTER TABLE ... SET LOGGED

On Thu, Aug 21, 2014 at 8:04 PM, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>
wrote:
> Andres Freund wrote:
>
> > Have you looked at the correctness of the patch itself? Last time I'd
> > looked it has fundamental correctness issues. I'd outlined a possible
> > solution, but I haven't looked since.
>
> Yeah, Fabrizio had it passing the relpersistence down to make_new_heap,
> so the transient table is created with the right setting. AFAICS it's
> good now. I'm a bit uneasy about the way it changes indexes: it just
> updates pg_class for them just before invoking the reindex in
> finish_heap_swap. I think it's correct as it stands though; at least,
> the rewrite phase happens with the right setting, so that if there are
> constraints being checked and these invoke index scans, such accesses
> would not leave buffers with the wrong setting in shared_buffers.
>

Ok.

> Another option would be to pass the new relpersistence down to
> finish_heap_swap, but that would be hugely complicated AFAICS.
>

I think isn't so complicated to do it, but will this improve something ?
Maybe I didn't understand it very well. IMHO it just complicate a
simple thing.

> Here's the updated patch.
>

Thanks Alvaro!

Regards,

--
Fabrízio de Royes Mello
Consultoria/Coaching PostgreSQL
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