Re: [Postgres-xc-general] ERROR: Failed to get pooled connections

[Michael P. <mic...@gm...>]

On 2012/07/30, at 22:52, Vladimir Stavrinov <vst...@gm...> wrote:

> On Mon, Jul 30, 2012 at 10:21:06PM +0900, Michael Paquier wrote:
> 
>>   - LB: There is an automatic load balancing between Datanodes and Coordinator by design. Load balancing at Coordinator
>>   level has to be managed by an external tool.
> 
> For read requests to replicated tables and write requests to distributed
> tables it is clear, it is true. But for write requests to replicated
> tables there are no LB. And for read requests to distributed tables we
> have quasi LB where requests for different data may go to different
> nodes, while requests for the same data still go to the same node.
Yes, replicated tables need to be used for master tables, the tables referred a lot and changed a little.
Well, honestly, there are some ways to provide what you are looking for. However there are currently no cluster product that can fully provide that with a complete multi master structure.

> 
>>     do You think about implementing different data node types (instead of
>>     tables), i.e. "distributed" and "replicated" nodes?
>> 
>>   Well, the only extension that XC adds is that, and it allows to perform either read and/or write scalability in a
>>   multi-master symmetric cluster, so that's a good deal!
> 
> I am not sure I understood You right. Does this means You support the
> idea to move distribution type from table level to node level?
No. Not directly. However you can also make all the tables to a specific node with the same type! If I understood that a distribution type at node level means that all the tables on this node have the same type, which is the type of the node.
> 
> -- 
> 
> ***************************
> ##  Vladimir Stavrinov
> ##  vst...@gm...
> ***************************
>