Hi,

cbbrowne at ca.afilias.info wrote:
>> Hi all,
>>
>>   I think the subject of this mail tel everything.  I search several
>> list and haven't found an answer to my question.  If Slony-I cannot do
>> the job is Mammoth can do it?  Or any other solution to replicate data
>> on a slave server!
>>     
>
> You mean that you have a PostgreSQL postmaster that has 250 databases
> (e.g. - you ran createdb 250 times) and each of those has ~150 tables?
>   
Yes


> That seems like a case that will not likely turn out well with Slony-I.
>
> The trouble is that Slony-I replicates from *a database* at a time.
>
> If you have 250 databases on that PG cluster, then you need to have 250
> slon processes, and, more than likely, 250 Slony-I clusters to manage.
>
> Further, supposing you want to have two backup servers, that'll mean...
>
> - 750 slon processes
> - For each one, probably 4 connections, hence 3000 database connections,
> 1000 per postmaster
>
> You'll find memory consumption to be hurtful, and this represents a pretty
> big "thundering herd" of replication apparatus.
>
> I'm not sure if Mammoth would provide you a better or worse experience, in
> this scenario.  I think you'll need to contact the vendor about that.
>   
Thanks for the info that really means I cannot use Slony-I but the PITR 
and WAL seem to be the right solution for my problem. 

Thanks for your help
/David


> The other possibility that I'd point to for situations like this is the
> new-in-version 8 Point In Time Recovery system for PostgreSQL.  It will
> NOT allow you to use the standby server(s) to respond to queries, alas. 
> But it would inexpensively address your "explosion" of schemas.
>
>
>
>
>