Re: Make unlogged table resets detectable

On Mon, Jun 7, 2021 at 11:46 PM Michael Paquier <michael@paquier.xyz> wrote:
> On Mon, Jun 07, 2021 at 02:56:57PM -0400, Tom Lane wrote:
> > +1.  I'd support recording the time of the last crash recovery, as
> > well as having a counter.  I think an LSN would not be as useful
> > as a timestamp.
>
> One could guess a timestamp based on a LSN, no?  So I'd like to think
> the opposite actually: a LSN would be more useful than a timestamp.

One could also guess an LSN based on a timestamp, but I think in
either case one has to be a pretty good guesser. The rate at which WAL
is generated is hardly guaranteed to be uniform, and if you're looking
at a system for the first time you may have no idea what it is.

-- 
Robert Haas
EDB: http://www.enterprisedb.com