Re: Replicating databases

It doesnt sound to me like replication is the right answer to this
problem... You are setting yourself up to try and defeat one of the major
purposes of a database in a client-server system -- namely -- centralized
storage.

If you add up all the money you are going to spend trying to manage multiple
copies of the same database along with all of the maintenance, support,
bandwidth, and costs of not allowing your end-users access to "real-time"
data (like making bad decisions based on aged data) -- I think you will
agree that it could end up being VERY expensive in the long term.

The part of your plan where you intend to synchronize all of the databases
overnight is still going to be a bottleneck.

A better alternative -- put some money into upgrading your bandwidth --
especially at the postgreSQL server end -- not necessarily at each location.

FWIW: I have a client with 472+ stores each using a 56K (fractional T1 pipe)
connection to a central postgreSQL server. They dont have any major
performance problems that I am aware of. If they did -- I can pretty much
guarantee that distributing 472 copies of the database would never ever be
considered as a "solution" to improve performance.



"Carlos Benkendorf" <carlosbenkendorf@yahoo.com.br> wrote in message
news:20051102120637.58061.qmail@web35507.mail.mud.yahoo.com...
Hello,

Currently our company has a lot of small stores distributed around the
country and in the actual database configuration we have a central database
and all the small stores accessing it remotely.

All primary key tables were designed with a column identifying the store
that it belongs. In other words, the store that can update the line, other
stores can read it but the system was designed in such a way that other
stores can not update information that do not belong to them.

The performance is not good because the line speed that connects the store
to the central database sometimes is overloaded. We�re thinking to replicate
the central database to each store. The store would be able to read all the
information from the local database but should only update lines that belong
to that store.

When a store needs read information about other stores, it is not necessary
to be updated, it can be a yesterday snapshot.

During the night all the local store databases will be consolidated in only
one database and replicated again to the stores. In the morning, when the
store opens, the local database has an updated and consolidated data.
I would appreciate suggestions about how the best way to implement such
soluction.

Slony-1? SQL scripts?

Thanks in advance!

Benkendorf
__________________________________________________
Fa�a liga��es para outros computadores com o novo Yahoo! Messenger
http://br.beta.messenger.yahoo.com/