Re: [HACKERS] Transaction ID wraparound: problem and proposed solution

[Hannu Krosing]

Peter Eisentraut wrote:
> 
> Hannu Krosing writes:
> 
> > > The first thought that comes to mind is that XIDs should be promoted to
> > > eight bytes.  However there are several practical problems with this:
> > > * portability --- I don't believe long long int exists on all the
> > > platforms we support.
> >
> > I suspect that gcc at least supports long long on all OS-s we support
> 
> Uh, we don't want to depend on gcc, do we?

I suspect that we do on many platforms (like *BSD, Linux and Win32).

What platforms we currently support don't have functional gcc ?

> But we could make the XID a struct of two 4-byte integers, at the obvious
> increase in storage size.

And a (hopefully) small performance hit on operations when defined as
macros,
and some more for less data fitting in cache.

what operations do we need to be defined ?

will >, <, ==, !=, >=, <== and ++ be enough ?

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Hannu