Subject Re: [ib-support] Replication
Author Paul Schmidt
On 11 Sep 2002 at 7:11, Michael Vilhelmsen wrote:

> Hi
> I have made a program which uses Firebird.
> This program has been sold to a some customers.
> Now some of these are about to open some new shops.
> So far we have used a Terminal Server in the head office, and then
> letting the clients connect to this server.
> But at this point we have a customer who does not wish to do it this
> way, but wants to have two seperated systems, which could replicate
> against each other (via internet or something like that).
> Is this posible ?
> And can I find some information on this subject somewhere ?

It depends on how well synchronized you want the two servers, if they have to be
mirror copies, then your best bet would be some kind of replication server. If they
do not need to be mirror copies, then you have more latitude. The key problem is
what do you do about unique keys. In many cases you can use a window, where
different offices use a different range of values. Just pump the records across using
either database tools or your own tools.

Here is an example:

200K records are entered by each office a year, so set the generator in one office to
0, and the generator at the other office to 20 000 000, it will take ~50 years before
the first office will catch up with the second office, by that time you will not care....
Once every 24 hours each office extracts the records added during that period, puts
them in a file, one office dials the other , and exchanges the files, each one then
updates it's own database using the file it copied from the other. This could be fully
automated or done by a person.

Paul Schmidt, President
Tricat Technologies