Re: lcr v5 - introduction of InvalidCommandId

On 2013-09-05 21:02:44 +0200, Andres Freund wrote:
> On 2013-09-05 14:37:01 -0400, Tom Lane wrote:
> > Andres Freund <andres(at)2ndquadrant(dot)com> writes:
> > > On 2013-09-05 14:21:33 -0400, Tom Lane wrote:
> > >> Ideally I'd have made InvalidCommandId = 0 and FirstCommandId = 1,
> > >> but I suppose we can't have that without an on-disk compatibility break.
> >
> > > The patch actually does change it exactly that way.
> >
> > Oh. I hadn't looked at the patch, but I had (mis)read what Robert said
> > to think that you were proposing introducing InvalidCommandId = 0xFFFFFFFF
> > while leaving FirstCommandId alone. That would make more sense to me as
> > (1) it doesn't change the interpretation of anything that's (likely to be)
> > on disk; (2) it allows the check for overflow in CommandCounterIncrement
> > to not involve recovering from an *actual* overflow. With the horsing
> > around we've been seeing from the gcc boys lately
>
> Ok, I can do it that way. LCR obviously shouldn't care.

It doesn't care to the point that the patch already does exactly what
you propose. It's just my memory that remembered things differently.

So, a very slightly updated patch attached.

Greetings,

Andres Freund

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