how to tell master from replica

On Wed, Sep 25, 2013 at 4:53 PM, Scott Ribe <scott_ribe@elevated-dev.com>wrote:

Assuming a master & replica set up using streaming replication, hot
standby, 9.3.

I'd like to have a single script on both machines distinguish whether it's
running on the machine with the master or replica, and take different
actions accordingly.

Is the way to do this to check for the presence of wal sender process vs
wal receiver process? Or is there a query that could executed against sys
tables to find current running config of the local postmaster?

Would pg_is_in_backup() do the job?

http://www.postgresql.org/docs/9.3/static/functions-admin.html#FUNCTIONS-ADMIN-BACKUP

On Thu, Sep 26, 2013 at 8:53 AM, Scott Ribe <scott_ribe@elevated-dev.com> wrote:

Assuming a master & replica set up using streaming replication, hot standby, 9.3.

I'd like to have a single script on both machines distinguish whether it's running on the machine with the master or replica, and take different actions accordingly.

Is the way to do this to check for the presence of wal sender process vs wal receiver process? Or is there a query that could executed against sys tables to find current running config of the local postmaster?

"SELECT pg_is_in_recovery();" can be used to make the difference
between a master and a slave.
--
Michael

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On Wed, Sep 25, 2013 at 5:11 PM, bricklen <bricklen@gmail.com> wrote:

On Wed, Sep 25, 2013 at 4:53 PM, Scott Ribe <scott_ribe@elevated-dev.com>wrote:

Assuming a master & replica set up using streaming replication, hot
standby, 9.3.

I'd like to have a single script on both machines distinguish whether
it's running on the machine with the master or replica, and take different
actions accordingly.

Is the way to do this to check for the presence of wal sender process vs
wal receiver process? Or is there a query that could executed against sys
tables to find current running config of the local postmaster?

Would pg_is_in_backup() do the job?

http://www.postgresql.org/docs/9.3/static/functions-admin.html#FUNCTIONS-ADMIN-BACKUP

Sorry, meant "pg_is_in_recovery()". (Michael's response tipped me off)

On Sep 25, 2013, at 6:13 PM, Michael Paquier <michael.paquier@gmail.com> wrote:

"SELECT pg_is_in_recovery();" can be used to make the difference
between a master and a slave.

Exactly what I need; thanks.

--
Scott Ribe
scott_ribe@elevated-dev.com
http://www.elevated-dev.com/
(303) 722-0567 voice

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