I have a master+slave set up using asynchronous streaming replication. If I
do a graceful (-fast) shutdown of the master, and then promote the slave to
master, my understanding is that I should not have any data loss. At that
point in order to bring the old master back up as a slave the docs say I
should do a base-backup etc....however I've found that simply
setting recovery_target_timeline='latest' does allow the old master to start
back up as a slave, and everything appears to be happy, all data seems to be
synced properly. My question is, is this safe to do? It's a very
attractive option as it removes a significant amount of load from the master
server for planned switch-overs (maintenance/upgrades/whatever). Thanks!