postgres-xc-developers Mailing List for Postgres-XC

On Jan 25, 2014, at 2:13 AM, Michael Meskes <me...@po...> wrote:

>> Really? You actually have RPMs that depend on Postgres, and add the XC functionality in a binary distribution?
> 
> No. First of all we have DEBs no RPMs. And second of all, what I was meaning to say it we have for instance a Postgres-XC server package, because that is different from PostgreSQL. But we do not have an XC libpq package.

Right. libpq should be included in your -libs package or something, right? psql won't work without it.

>> But the XC docs include everything from the pg docs, no?
> 
> Yes, afaict.

That’s what I thought.

Thanks,

David

On Fri, Jan 24, 2014 at 02:17:13PM -0800, David E. Wheeler wrote:
> > We haven't completely solved the coexistance part yet, but mainly due to time
> > constraints. What we do so far is only build those pieces of XC that are
> > different and rely on the PG packages for the rest.
> 
> Really? You actually have RPMs that depend on Postgres, and add the XC functionality in a binary distribution?

No. First of all we have DEBs no RPMs. And second of all, what I was meaning to say it we have for instance a Postgres-XC server package, because that is different from PostgreSQL. But we do not have an XC libpq package.

> > I think they have to be part of it. After all people might just install XC
> > without PG alongside it.
> 
> But the XC docs include everything from the pg docs, no?

Yes, afaict.

Michael
-- 
Michael Meskes
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Hi All,

I am thinking 3 choices as below:

1. Pacemaker and Corosync.
I have little experience on Linux HA, so one week passed, I even can not install them successfully, including Pacemaker/Corosync/crmsh/resouce agent. 
There are some website mentioned Pacemaker/corosync can help PGXC to build a HA infrastructure, but I can not find a comprehensive guide to do it. There are much more commponents in PGXC than PG, I think I should learn how to build it based on PG first. 

2. Zookeeper
It seems that Zookeeper has the ability to build a HA solution for PGXC, which have the similar function with Pacemaker, but I have to develop the heartbeat function for Zookeeper to start/stop/monitor/failover PGXC. And I do not know if my understand is right.

3. PGXC support HA internally. 
Because the table of pgxc_nodes in coordinator already have some information about the cluster, it can be enhanced to save the Master/Slave relations, it is replicated between all coordinators, then it can used as a CRM(Cluster Resource Management, as Pacemaker) compoment. 
And the coordinator will connect to datanode/gtm/other coordinator in its regular work, so the heartbeat function exists natually. Even when the database is in the spare time, the coordinator can send a simple query as "select 1+1" to datanodes as the heartbeat ticks. 
What need to do is that, the coordinator will start a new process when starting, the new process will act as a heartbeat /resouce_agent to monitor the cluster status, and restart/failover once one commponent fails. 

As my initial understanding, Choice 3 is better than Choice 2 which is better than Choice 1. But for the development effort, the order is reversed, Choice 1 is easy achieved based on current existing codes. 

I am very appreciated that you can share your advice with me.

Thanks 
Julian