On Mon, 2020-01-27 at 16:01 +0000, soumik.bhattacharjee@xxxxxxx wrote: > I set the "wal_log_hints = on" , but enabling this parameter "on" in new MASTER(old SLAVE) needs a restart-- > which I cannot do as all application transactions are going on there now. > > Also I used pg_rewind in old MASTER(which now I want to make as new SLAVE) and it was successful, > but this also needs restart of new MASTER(old SLAVE) which is again an issue. > > Command used: ./pg_rewind -D $PGDATA --source-server='host=<IP Address> port=5432 user=postgres password=xxxx > > Could you please suggest how to get this to work to keep the MASTER(old SLAVE) up & running and make the old MASTER(new SLAVE) If you want to use "pg_rewind", you have to plan for that ahead of time by either using data page checksums or enabling "wal_log_hints". The first requires longer don time, the second a restart. There is no way to do that retroactively. Just use "pg_basebackup" to create a new standby, and enable "wal_log_hints" next time you get a chance to restart. Yours, Laurenz Albe -- Cybertec | https://www.cybertec-postgresql.com
