Re: Should we add xid_current() or a int8->xid cast?

Thomas Munro <thomas.munro@gmail.com>

From: Thomas Munro <thomas.munro@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Andres Freund <andres@anarazel.de>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2019-07-25T01:11:59Z
Lists: pgsql-hackers
On Thu, Jul 25, 2019 at 12:42 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Andres Freund <andres@anarazel.de> writes:
> > On 2019-07-24 20:34:39 -0400, Tom Lane wrote:
> >> Yeah, I would absolutely NOT recommend that you open that can of worms
> >> right now.  We have looked at adding unsigned integer types in the past
> >> and it looked like a mess.
>
> > I assume Thomas was thinking more of another bespoke type like xid, just
> > wider.  There's some notational advantage in not being able to
> > immediately do math etc on xids.
>
> Well, we could invent an xid8 type if we want, just don't try to make
> it part of the numeric hierarchy (as indeed xid isn't).

Yeah, I meant an xid64/xid8/fxid/pg_something/... type that isn't a
kind of number.

-- 
Thomas Munro
https://enterprisedb.com



Commits

  1. Introduce xid8-based functions to replace txid_XXX.

  2. Add SQL type xid8 to expose FullTransactionId to users.

  3. Replace the former method of determining snapshot xmax --- to wit, calling