On 6/17/2005 2:59 PM, John Surnow wrote:
>  
> 
> Why does each slave node communicate with every other slave node?

Because there are no "slave nodes" to begin with. Slony-I consists of a 
network of equal nodes, all communicating with each other in a sort of 
reliable message passing system implemented using PostgreSQL. While at 
it, they can also exchange information about changes that happened to 
user tables. So what you call replication is basically a usefull side 
effect in the Slony-I case.

In the upcoming version 1.1 you will have the ability to have additional 
offline leaf nodes via log shipping. Those do not run a slon daemon and 
are not even known in the replication cluster configuration.

> 
>  
> 
> What will happen if a slave node is down for a long time?

"Long time" depends mainly on the update activity and sync frequency of 
your database. That said, all messages and all data change information 
(replication log) will pile up. There will be a point where the 
administrator should decide that it is "cheaper" to abandon the node, 
throw away the piled up log data (by dropping the node from the 
configuration) and rebuild it from scratch when it comes back to life.


Jan

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