Re: Advanced Replication: What is the best design for our situation?

Jeroen Pieters wrote:
> To everybody who has a lot of experience with Oracle Advanced
> Replication,
>
> We have to come up with a design of an Oracle distributed database for
> the following situation:
>
> We have 5 vessels (A,B,C,D and E), all at a fixed position for a fixed
> period of time. We have a head quarters (HQ) and 3 base offices
> (1,2,3).
>
> Base office 1 and 2 are connected to our HQ with a 2M leased line.
> Base office 3 is connected to base office 1 with a 128K leased line.
> Vessels A,B,C and D are connected to base office 1 with a 192K
> satelite link.
> Vessel E is connected to base office 2 with a 128K satelite link.
>
> On all vessels an application shall be used, provided by an
> application server, which can be accessed by a web browser. The same
> application shall also be used in the base offices and in HQ.
>
> Preferably we use 1 database with 1 application server in our HQ, but
> because of our WAN limitations and the uptime of the satelite links,
> we have to come up with a different solution.
>
> We are thinking of the following options:
> 1. Multi-Master setup across all vessels and HQ.
> 2. Single Master setup with Materialized View Sites on the vessels.
> 3. .......
>
> The application has about 200 tables, with an average rowcount of
> 20000 records per table. Most of the business logic resides in the
> application, not in the database. Therefore it is a pretty much
> straith forward database...no exotic features are used.
>
> What we are interested in:
> 1. Is there anyone with a similar problem, who likes to share his
> experience with us?
> 2. Are there any other solutions possible what we didn't think of?
> 3. Is there anyone who has some real-life experience with Materialized
> View Sites setup like our situation? We would like to know if this
> setup is manageable?
> 4. Are there any 3rd party tools who are easy to manage/install and
> can help us with our problem.
>
> Thanks in advance for all relevant comment.
>
> If you need any more details, put it in the thread and I'll update it.
>
> Best regards,
> Jeroen Pieters

Sigh....
No oracle version, bad design, no clue....

1. Similar problem - no; challenge, yes: 140 salesmen, dial-in lines, client/server application.
2. depends heavily on oracle version
3. setup is always manageable, but it can be hard to get results. Think what would happen if 4 out of your 8 offices are out-of-sync; not only to the main server, but also to the 'truth' (implying the main server is incorrect, too - indeed).
4. Don't know. Oracle can do it, at no additional costs, so why bother?

MultiMaster replication is only applicable if *all* sites need the same information, as well as update/insert/delete capabilities. I can hardly imagine, vessels need as much information as HQ; in that case updatable materialized views would be appropriate. The more business rules and constraints in the database, the better. It is now very possible to replicate and introduce consistency errors, just because your application design flawed. It's not J2EE, is it?

-- 
Regards,
Frank van Bortel