Re: [ADMIN] Can master and slave on different PG versions?

On Wed, Nov 8, 2017 at 9:47 PM, rammohan ganapavarapu <rammohanganap@gmail.com> wrote:

David,

So initially i have physical replication configured, so to upgrade slave to 9.6 version i did converted master slave to logical replication and then try to upgrade the slave to 9.6. I am getting this error when i try to start the slave. Any idea?

2017-11-08 05:08:49 UTC [20063]: [1-1] user= db= host= LOG:  shutting down

2017-11-08 05:08:49 UTC [20063]: [2-1] user= db= host= LOG:  database system is shut down

2017-11-08 05:09:45 UTC [20322]: [1-1] user= db= host= LOG:  database system was shut down at 2017-11-08 05:08:55 UTC

2017-11-08 05:09:45 UTC [20322]: [2-1] user= db= host= LOG:  entering standby mode

2017-11-08 05:09:45 UTC [20322]: [3-1] user= db= host= WARNING:  WAL was generated with wal_level=minimal, data may be missing

2017-11-08 05:09:45 UTC [20322]: [4-1] user= db= host= HINT:  This happens if you temporarily set wal_level=minimal without taking a new base backup.

2017-11-08 05:09:45 UTC [20322]: [5-1] user= db= host= FATAL:  hot standby is not possible because wal_level was not set to "replica" or higher on the master server

2017-11-08 05:09:45 UTC [20322]: [6-1] user= db= host= HINT:  Either set wal_level to "replica" on the master, or turn off hot_standby here.

2017-11-08 05:09:45 UTC [20312]: [3-1] user= db= host= LOG:  startup process (PID 20322) exited with exit code 1

2017-11-08 05:09:45 UTC [20312]: [4-1] user= db= host= LOG:  aborting startup due to startup process failure

2017-11-08 05:09:45 UTC [20312]: [5-1] user= db= host= LOG:  database system is shut down

Thanks,

Ram

On Mon, Oct 9, 2017 at 4:15 PM, David G. Johnston <david.g.johnston@gmail.com> wrote:

On Mon, Oct 9, 2017 at 4:06 PM, rammohan ganapavarapu <rammohanganap@gmail.com> wrote:

Hi,

Is it possible to add 9.6 version Slave to 9.4 master?

​Physical replication, no;  Logical replication, yes - if the software you are using is compatible with both versions.

David J.​

In addition to above, Slony also an option for keeping master & slave on different versions which play a key role during upgrades for reducing downtime drastically.

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