Re: Cascade streaming replication + wal_files - Pgsql 9.2

On Thu, 7 Jul 2016, 9:20 a.m. Patrick B, <patrickbakerbr@gmail.com> wrote:

Hi guys,

I got two slaves using Postgresql 9.2.

slave01 - Streaming replication from master

slave02 - nothing.. new server

is it possible to get slave02 replicating from slave01 (Cascade streaming replication) this can be done with streaming ?

Yes, a cascaded standby can be setup with Streaming Replication in v9.2 and above.

and also slave01 sending the wal_files to that new slave02?

What exactly do you mean here by "sending the wal_files"??

So it would be on slave01

archive_mode = ok 

archive_command = ....

This will have no effect on a standby server. archive_command will be neglected

This is possible only in v9.5 onward when archive_mode is set to always.

wal_level = hot_standby

max_wal_senders = 2

wal_keep_segments = 128

Is that right?

If you want to set up archiving from slave01, checkout pg_receivexlog.

https://www.postgresql.org/docs/9.2/static/app-pgreceivexlog.html

It might be helpful as it does something similar to archiving but using streaming protocol (so I think it should work even in cascaded mode). But since it works using streaming protocol, max_wal_senders on slave01 will be 2(what you have set now) + 1 (for pg_reveivexlog)

ok.. got a little confused now.

the only way to archive the wal_files from a slave into another slave on PostgreSQL 9.2, is by using pg_reveivexlog?