On Wed, Jan 23, 2019 at 11:17 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> On Thu, Jan 24, 2019 at 3:39 AM John Naylor <john.naylor@2ndquadrant.com> wrote:
> > mkdir -p data1 data2 standby
> >
> > echo 'heap' > data1/foo
> > echo 'fsm' > data1/foo_fsm
> >
> > # simulate streaming replication
> > rsync --archive data1 standby
> >
> > # simulate pg_upgrade, skipping FSM
> > ln data1/foo -t data2/
> >
> > rsync --archive --delete --hard-links --size-only --no-inc-recursive
> > data1 data2 standby
> >
> > # result
> > ls standby/data1
> > ls standby/data2
> >
> >
> > The result is that foo_fsm is not copied to standby/data2, contrary to
> > what the docs above imply for other unlinked files. Can anyone shed
> > light on this?
> >
>
> Is foo_fsm present in standby/data1?
Yes it is.
> I think what doc means to say is
> that it copies any unlinked files present in primary's new cluster
> (which in your case will be data2).
In that case, I'm still confused why that doc says, "Unfortunately,
rsync needlessly copies files associated with temporary and unlogged
tables because these files don't normally exist on standby servers."
I fail to see why the primary's new cluster would have these if they
weren't linked. And in the case we're discussing here, the skipped
FSMs won't be on data2, so won't end up in standby/data2.
--
John Naylor https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
