Re: HOT updates & REDIRECT line pointers

On Wed, Mar 21, 2012 at 09:28:22PM -0400, Robert Haas wrote:
> On Wed, Mar 21, 2012 at 9:22 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> >> It strikes me that it likely wouldn't be any
> >> worse than, oh, say, flipping the default value of
> >> standard_conforming_strings,
> >
> > Really?  It's taking away functionality and not supplying any substitute
> > (or at least you did not propose any).  In fact, you didn't even suggest
> > exactly how you propose to not break joined UPDATE/DELETE.
>
> Oh, hmm, interesting. I had been thinking that you were talking about
> a case where *user code* was relying on the semantics of the TID,
> which has always struck me as an implementation detail that users
> probably shouldn't get too attached to. But now I see that you're
> talking about something much more basic - the fundamental
> implementation of UPDATE and DELETE relies on the TID not changing
> under them. That pretty much kills this idea dead in the water.

Should this information be added to src/backend/access/heap/README.HOT?

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ It's impossible for everything to be true. +