Re: So, why shouldn't SET CONSTRAINTS set a transaction snapshot?

Tom Lane wrote:
> Alvaro Herrera <alvherre@commandprompt.com> writes:
> > Tom Lane wrote:
> >> 1. Always set a snapshot for SET CONSTRAINTS.  This is a minus-one-liner
> >> --- just remove it from the exclusion list in PortalRunUtility.
> >> 
> >> 2. Have it set a snapshot only if it finds pending trigger events to
> >> fire.  This would only require another half dozen lines of code, but
> >> it's certainly more complicated than choice #1.
> 
> > It seems to me there is room for a backwards compatibility argument
> > here.  How about doing #2 for 8.3 and back, and #1 for 8.4?
> 
> Well, if you think there's a real backwards compatibility issue, we
> should just do #2 and be done with it.  It's not like it's enough code
> to really matter in the big scheme of things.

I don't like it just because it's another kludge in the way we set up
ActiveSnapshot.  I think it would be better if we were simplifying that
code, not adding more kludges.

If there's no backwards compatibility argument (and from the looks of
your patch, perhaps there wouldn't), then I think we should just do #1.

-- 
Alvaro Herrera                                http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support