On 9/9/2007 1:58 PM, Filip Rembiałkowski wrote:
> 2007/9/9, Tim Bowden <tim.bowden at westnet.com.au>:
> 
>>  Hopefully that will scale well as I've
>> got 100+ master db's.
> 
> over 100 partitions? you should be careful as slony1 has some
> communication overhead  which grows quadratically with the number of
> nodes in a cluster.
> 
> google for "slony communication costs"
> 
> I'm not sure if it applies to your situation though... I've never
> tested such setup, maybe we should wait untill someone more
> experienced gives a word about it
> 
> maybe I should not say this here ... but at worst, you will have to
> drop slony in favour of other (simpler) solution - like home-made
> trigger-based tool or other replication engine (londiste?)

No problem with saying that here. It is a valid concern and points to a 
known weakness in Slony, so Tim knows right away what to test first (now 
having a 100+ node test cluster is of cause a different story).

The new logshipper tool I just added to the CVS tree (not released yet) 
might be of help here. It would certainly be possible to divide the 
whole bunch of locations into several regions and replicate each of them 
into a region specific central slave. All those would use slony archives 
and the logshipper to consolidate into one central database.


Jan

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