Simon Riggs <simon at 2ndquadrant.com> writes:
> slony is normally described as a master-slave replication system.
>
> I'm sure I could set this up to try, but it seems easier to ask a
> straight question on it. I'm sorry but I've not found previous Q/As to
> answer this one simply enough for me to be clear.
>
> Any table can have one source. That seems to allow me to setup links so
> that:
>
> System1.Table1 -> System2.Table1
> System2.Table2 -> System1.Table2
>
> Yes? Good. Will that work for inherited tables too? Can I have:
>
> System1.Child1 inherits System1.Parent
> System1.Child2 inherits System1.Parent
>
> System2.Child1 inherits System2.Parent
> System2.Child2 inherits System2.Parent
>
> System1.Child1 -> System2.Child1
> System2.Child2 -> System1.Child2
>
> which is close enough to multi-master replication for most designs.
>
> So if I ask for Parent on either system I get the same data (ignoring
> the data delay complication for the moment) ?
>
> Does slony also allow me to do this:
>
> CentralSystem.ChildN inherits CentralSystem.Parent
>
> System1.Table1 -> CentralSystem.Child1
> ...
> SystemN.Table1 -> CentralSystem.ChildN
>
> which is the central rollup scenario.

In principle, it ought to be possible.

Someone ought to try it to see if it works...

The one problem I'd foresee is that indices aren't shared across such
inheritance scenarios, so if the "child" tables get large, queries
across the "parent" might wind up not being as efficient as you'd
want.
-- 
"cbbrowne","@","ca.afilias.info"
<http://dev6.int.libertyrms.com/>
Christopher Browne
(416) 673-4124 (land)