Re: Usage of epoch in txid_current

On Thu, Mar 28, 2019 at 1:48 AM Heikki Linnakangas <hlinnaka@iki.fi> wrote:
> Once we have the FullTransactionId type and basic macros in place, I'm
> sure we could tidy up a bunch of code by using them. For example,
> TransactionIdInRecentPast() in walsender.c would be simpler, if the
> caller dealt with FullTransactionIds rather than xid+epoch. But it makes
> sense to do that separately.

+1

> > +     /*
> > +      * It is safe to read nextFullXid without a lock, because this is only
> > +      * called from the startup process, meaning that no other process can
> > +      * modify it.
> > +      */
> > +     Assert(AmStartupProcess());
> > +
>
> This assertion fails on WAL replay in single-user mode:

Fixed.  (Embarrassingly I had that working in v7 but broke it in v8).

I decided to do some testing on a 32 bit system, and ran into weird
new problem in heap_compute_xid_horizon_for_tuples() which I assumed
to be somehow my fault due to the mention of xid horizons, but I
eventually realised that master was broken on that machine and
followed that up elsewhere.  Phew.

Thanks for the reviews!  Pushed.

-- 
Thomas Munro
https://enterprisedb.com