When commit 0f33a719fd removed the
instructions to start/stop the new cluster before running rsync, it was
now possible for pg_resetwal/pg_resetxlog to leave the final WAL record
at wal_level=minimum, preventing upgraded standby servers from
reconnecting.
This patch fixes that by having pg_upgrade unconditionally start/stop
the new cluster after pg_resetwal/pg_resetxlog has run.
Backpatch through 9.2 since, though the instructions were added in PG
9.5, they worked all the way back to 9.2.
Discussion: https://postgr.es/m/20170620171844.GC24975@momjian.us
Backpatch-through: 9.2
a0e8548811