On 30/01/2018 09:48, Luca Ferrari wrote:
Hi all,
now this should be trivial, but I cannot udnerstand what is the
purpose of session_replication_role
<https://www.postgresql.org/docs/10/static/runtime-config-client.html#GUC-SESSION-REPLICATION-ROLE>
or better, when I should use it in a way different from 'origin'.
I've a logical replication setup and both master and client
connections default to 'origin', so it has to be specified manually.
What is its meaning?
This has an effect on dictating how triggers are fired.
For instance if you have built your proprietary replication mechanism based on triggers (e.g. Slony, DBmirror) then you might want at certain occasions (e.g. reading xactions from a master) to avoid
firing triggers in order e.g. to prevent bounce back messages to the originator. If your replication trigger is a simply enabled trigger, then by setting session_replication_role to replica will
prevent the trigger from firing. This could be useful in the code where you execute SQL originating from the master, in order not to send those back and cause an endless loop.
Thanks,
Luca
--
Achilleas Mantzios
IT DEV Lead
IT DEPT
Dynacom Tankers Mgmt
