Re: Replication

Hannu Krosing wrote:
> But if you have very few writes, then there seems no reason to do sync
> anyway.

I think there is one: high-availability. A standby-server which can 
continue if your primary fails. Of course sync is only needed if you 
absolutely cannot effort loosing any committed transaction.

>> Another important factor is the amount of conflicting transactions.
> 
> That too, but just the need to do *any* locking on all nodes will
> significantly slow down sync replication

If you implement sync replication with locking, yes. But there are 
better ways: the Postgres-R approach does not do network locking, but 
aborts conflicting transactions just before committing. That results in 
much less network traffic (one GCS-message per writing-transaction).

Regards

Markus