Re: Fatal error after starting postgres : sys identifiers must be different

On Fri, Jul 19, 2013 at 5:02 AM, Indrajit Roychoudhury
<indrajit.roychoudhury@gmail.com> wrote:
> Could you please let me know what does the error "system identifiers are
> same" mean? Below is the snapshot from one of the masters.
> I am setting up BDR as per the wiki
>   http://wiki.postgresql.org/wiki/BDR_User_Guide#Initial_setup
> and source @
>  git://git.postgresql.org/git/users/andresfreund/postgres.git
>
> irc1@ubuntuirc:~/bdr2/postgres-d6ed89e/postgres-bdr-bin/bin$ ./postgres -D
> ~/bdr2/postgres-d6ed89e/postgres-bdr-bin/bin/data2/
> LOG:  bgworkers, connection: dbname=testdb2
> LOG:  option: dbname, val: testdb2
> LOG:  registering background worker: bdr apply: ubuntuirc2
> LOG:  loaded library "bdr"
> LOG:  database system was shut down at 2013-03-17 10:56:52 PDT
> LOG:  doing logical startup from 0/17B6410
> LOG:  starting up replication identifier with ckpt at 0/17B6410
> LOG:  autovacuum launcher started
> LOG:  starting background worker process "bdr apply: ubuntuirc2"
> LOG:  database system is ready to accept connections
> LOG:  bdr apply: ubuntuirc2 initialized on testdb2, remote dbname=testdb2
> replication=true fallback_application_name=bdr
> FATAL:  system identifiers must differ between the nodes
> DETAIL:  Both system identifiers are 5856368744762683487.
I am not the best specialist about logical replication, but as it
looks to be a requirement to have 2 nodes with different system
identifiers, you shouldn't link 1 node to another node whose data
folder has been created from the base backup of the former (for
example create the 2nd node based on a base backup of the 1st node).
The error returned here would mean so.

> LOG:  worker process: bdr apply: ubuntuirc2 (PID 16712) exited with exit
> code 1
> ^CLOG:  received fast shutdown request
> LOG:  aborting any active transactions
> LOG:  autovacuum launcher shutting down
> LOG:  shutting down
>
> pgcontrol_data outputs different database system ids for the two nodes. So
> don't understand why it says identifiers are same.
Are you sure? Please re-ckeck.

> postgresql.conf content in one of the masters is like this-
>
> /////////////////
> shared_preload_libraries = 'bdr'
> bdr.connections = 'ubuntuirc2'
> bdr.ubuntuirc2.dsn = 'dbname=testdb2'
> /////////////////
>
> Two nodes are ubuntuirc and ubuntuirc2. Above is the output of the
> postgresql.conf from ubuntuirc.
If this behavior is confirmed, I think that this bug should be
reported directly to Andres and not this mailing list, just because
logical replication is not integrated into Postgres core as of now.
--
Michael