Horton

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

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
Cc: Thomas Munro <thomas.munro@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2019-07-25T00:42:30Z
Lists: pgsql-hackers 
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).

			regards, tom lane

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