Postgres replication

Hi,

The replication worked fine until the server re-start on Master we did recently this morning. After the restart of the linux server, I have started the database backup on Master however when I logged on to the slave server I saw the replication is terminated between the master and the slave.

Here is the status of the slave when I queried pg_stat_replication table:

postgres=# select * from pg_stat_replication ;
pid | usesysid | usename | application_name | client_addr | client_hostname | client_port | backend_start | backend_xmin | state
| sent_location | write_location | flush_location | replay_location | sync_priority | sync_state
-----+----------+---------+------------------+-------------+-----------------+-------------+---------------+--------------+-------
+---------------+----------------+----------------+-----------------+---------------+------------
(0 rows)

Does we have to re-initiate the replication every time on postgres if we restart either the Master/Slave Server. If so how can I re-initiate the replication.

Please let me know your thoughts on this.

Thank You,
Sajan Gone
Database Administrator
L Brands
Mobile #: 517-990-5282
Office #:   614-577-7622

From: Samed YILDIRIM <samed(at)reddoc(dot)net<mailto:samed(at)reddoc(dot)net>>
Date: Friday, April 14, 2017 at 10:34 AM
To: Sajan Gone <sgone(at)lb(dot)com<mailto:sgone(at)lb(dot)com>>, "pgsql-admin(at)postgresql(dot)org<mailto:pgsql-admin(at)postgresql(dot)org>" <pgsql-admin(at)postgresql(dot)org<mailto:pgsql-admin(at)postgresql(dot)org>>
Subject: Re: [ADMIN] Postgres replication

Hi Sajan,

You can use following query.

select * from pg_stat_replication;

Best regards.
Samed YILDIRIM

14.04.2017, 17:20, "Gone, Sajan" <sgone(at)lb(dot)com<mailto:sgone(at)lb(dot)com>>:
Hi Samed,

Thanks for sending out the weblink. I was able to successfully set the replication up (Master/Slave, Hot stand by).

I really appreciate your help on this.

My background is mostly on MySQL so my next question would be on how to look at the replication status. Like MySQL “Show slave status \G” command is there any command on postgres to look at the slave current status(or replication status).

Thank You,
Sajan Gone.
From: Samed YILDIRIM <samed(at)reddoc(dot)net<mailto:samed(at)reddoc(dot)net>>
Date: Thursday, April 13, 2017 at 4:27 PM
To: Sajan Gone <sgone(at)lb(dot)com<mailto:sgone(at)lb(dot)com>>, "pgsql-admin(at)postgresql(dot)org<mailto:pgsql-admin(at)postgresql(dot)org>" <pgsql-admin(at)postgresql(dot)org<mailto:pgsql-admin(at)postgresql(dot)org>>
Subject: Re: [ADMIN] Postgres replication

Hi Sajan,

You can take a look following document. It is good for a start point.

https://www.digitalocean.com/community/tutorials/how-to-set-up-master-slave-replication-on-postgresql-on-an-ubuntu-12-04-vps<https://urldefense.proofpoint.com/v2/url?u=https-3A__www.digitalocean.com_community_tutorials_how-2Dto-2Dset-2Dup-2Dmaster-2Dslave-2Dreplication-2Don-2Dpostgresql-2Don-2Dan-2Dubuntu-2D12-2D04-2Dvps&d=DwMGaQ&c=spYp1tZ3AQD6dfuI6rqaeg&r=7n1bLwXDzepgjKSNziw-ng&m=fHbva-Ii918KntE6AvrhZBUaeKjC9nKfhVNdqTAkYU8&s=GAJTCqC_l4UPTLi3vPPGwcbfSz80O79T1x6GJGA_JTU&e=>

Best regards.

22:25, 13 Nisan 2017, "Gone, Sajan" <sgone(at)lb(dot)com<mailto:sgone(at)lb(dot)com>>:

Hello,

Good afternoon everyone.

This is Sajan Gone, I am trying to setup a Standard Master/Salve replication between two postgres instances. I am pretty much new to postgres and not exactly sure how replication works and what is an architecture behind
it. As of now I am following the standard postgres documentation @ https://www.postgresql.org/docs/current/static/warm-standby.html#PREPARING-MASTER-FOR-STANDBY<https://urldefense.proofpoint.com/v2/url?u=https-3A__www.postgresql.org_docs_current_static_warm-2Dstandby.html-23PREPARING-2DMASTER-2DFOR-2DSTANDBY&d=DwMGaQ&c=spYp1tZ3AQD6dfuI6rqaeg&r=7n1bLwXDzepgjKSNziw-ng&m=Vi2JxqEOxr992ibCDezMAd_sbdja65aRxMh4oM6WYpo&s=Qb_JJynxAr1X-KEpv8g-FVJ4Ac4wuqLr6fR3IfEVNpo&e=>,
however it is slightly difficult for me to understand.

It would be very helpful if any one could guide me in a proper way on setting up Master/Slave replication on postgres. Any recommendations on good documentation
or study materials on postgres replication would be highly appreciated.

Many Thanks in advance.

Thank You,

Sajan Gone

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Notice: This communication may contain privileged and/or confidential information. If you are not the intended recipient, please notify the sender by email, and immediately delete the message and any attachments without copying or disclosing them. LB may, for any reason, intercept, access, use, and disclose any information that is communicated by or through, or which is stored on, its networks, applications, services, and devices.