On Mon, Jun 5, 2017 at 07:38:43PM -0700, Andres Freund wrote:
> On 2017-06-05 22:34:17 -0400, Bruce Momjian wrote:
> > On Mon, Jun 5, 2017 at 04:38:32PM -0500, Jerry Sievers wrote:
> > > The SAN snaps capture the entire pgdata and WAL pg_xlog area but there
> > > is no attempt to copy the NVME device when the snaps are made.
> > >
> > > There's an event trigger plus batch job now running tou avoid this risk.
> > >
> > > We realize too that there are implications here if a backup is
> > > instantiated and PITR is done.
> > >
> > > Just FYI that there could be others running like this ignorant of the
> > > potential gotchas.
> >
> > Yes, if we implement the TODO you will create a TEMPORARY tablespace
> > that can't contain non-temporary and/or non-unlogged tables.
>
> FWIW, allowing UNLOGGED tables, rather than just TEMPORARY ones,
> increases the complexity of that project noticeably. For TEMPORARY you
> basically don't need to do much but to recreate the structure inside the
> tablespace at start - fairly simple. But for UNLOGGED you need to find
> a way to recreate the relevant file and init forks - otherwise we might
> not notice what needs to be reset at a crash restart, and we might error
> out when executing selects etc. and then the table's not there.
> Presumably recreating files & init forks that at first table access is
> doable, but it's not entirely trivial to do locking wise.
Agreed, that is why they are separate adjacent items on the TODO list.
:-)
-- Bruce Momjian <bruce@momjian.us> http://momjian.us EnterpriseDB
http://enterprisedb.com
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