Re: [Postgres-xc-developers] proxy setup on standby server

[Koichi S. <koi...@gm...>]

Only after promotion.   Before promotion, they will not be connected
to gtm_proxy.

Regards;
----------
Koichi Suzuki


2013/3/21 Bei Xu <be...@ad...>:
> Hi Koichi:
>      Thanks for the reply. I still have doubts for item 1.  If we setup
> proxy on server 4, do we reconfigure server 4's coordinator/datanodes to
> point to server 4's proxy at ALL TIME(after replication is setup, I can
> change gtm_host to point to server4's proxy before I bring up slaves) or
> only AFTER promotion?
>
>
> On 3/20/13 11:08 PM, "Koichi Suzuki" <koi...@gm...> wrote:
>
>>1. It's better to have gtm proxy at server 4 when you failover to this
>>server.   We need gtm proxy now to failover GTM while
>>coordinators/datanodes are running.   When you simply make a copy of
>>coordinator/datanode with pg_basebackup and promote them, they will
>>try to connect to gtm_proxy at server3.   You need to reconfigure them
>>to connect to gtm_proxy at server4.
>>
>>2. Only one risk is the recovery point could be different from
>>component to component, I mean, some transaction may be committed at
>>some node but aborted at another because there could be some
>>difference in available WAL records.   It may possible to improve the
>>core to handle this to some extent but please understand there will be
>>some corner case, especially if DDL is involved in such a case.  This
>>chance could be small and you may be able to correct this manually or
>>this can be allowed in some applications.
>>
>>Regards;
>>----------
>>Koichi Suzuki
>>
>>
>>2013/3/21 Bei Xu <be...@ad...>:
>>> Hi, I want to set up HA for pgxc, please see below for my current setup.
>>>
>>> server1: 1 GTM
>>> server2: 1 GTM_Standby
>>> server3 (master):  1 proxy
>>>                                   1 coordinator
>>>                                   2 datanode
>>>
>>> Server4: (stream replication slave) :  1 standalone proxy ??
>>>                                   1 replicated coordinator (slave of
>>> server3's coordinator)
>>>                                    2 replicated datanode  (slave of
>>> server3's datanodes)
>>>
>>>
>>> server3's coordinator and datanodes are the master of the server4's
>>> coordinator/datanodes by stream replication.
>>>
>>> Question.
>>> 1. Should there be a proxy on server 4?   If not, which proxy  should
>>>the
>>> server4's coordinator and datanodes pointing to? (I have to specify the
>>> gtm_host in postgresql.conf)/
>>> 2. Do I have to use synchronous replication vs Asynchrous replication?
>>>I am
>>> currently using Asynchrnous replication because I think if I use
>>> synchronous, slave failour will affect master.
>>>
>>>
>>>-------------------------------------------------------------------------
>>>-----
>>> Everyone hates slow websites. So do we.
>>> Make your web apps faster with AppDynamics
>>> Download AppDynamics Lite for free today:
>>> http://p.sf.net/sfu/appdyn_d2d_mar
>>> _______________________________________________
>>> Postgres-xc-developers mailing list
>>> Pos...@li...
>>> https://lists.sourceforge.net/lists/listinfo/postgres-xc-developers
>>>
>>
>
>