Re: [PATCH] bigint txids vs 'xid' type, new txid_recent(bigint) => xid

On 16 August 2016 at 20:58, Greg Stark <stark(at)mit(dot)edu> wrote:

> On Tue, Aug 16, 2016 at 10:15 AM, Craig Ringer <craig(at)2ndquadrant(dot)com>
> wrote:
> > I'm surprised the 32-bit xid was ever exposed to the user, rather than a
> > 64-bit epoch-extended xid.
>
> Once upon a time we didn't have epoch counting at all.
>

Makes sense. I didn't dig back too far in history.

Sounds like you're in favour of the 2nd part of the proposal (not covered
by the current patch) then.

I haven't yet done the validation required on the epoch logic btw, and I
won't be too surprised if it's a bit off. I'm writing a fast xid burn
function for use in testing now. I doubt it'll be fast enough to use in
routine regression testing since all those clog pages will still take time.
But we'll see. I'd kind of like to be able to avoid all that - advance the
xid counter and treat all the old xids as frozen. I don't know or if this
is practical within a normal backend though.

Anyway, will follow up with more tests and - probably - a bugfix or three
soon.

--
Craig Ringer http://www.2ndQuadrant.com/
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