Re: Cascade streaming replication + wal_files - Pgsql 9.2

On Thu, 7 Jul 2016, 9:51 a.m. Patrick B, <patrickbakerbr(at)gmail(dot)com> wrote:

>
>>
>> On Thu, 7 Jul 2016, 9:20 a.m. Patrick B, <patrickbakerbr(at)gmail(dot)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.
>

I thought I did my best to explain :)

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

Yes. Though I have never tried this myself but going by the theory, it
should work.

> --
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