Re: Oracle7 7.3.3 Replication Design

Hi Stefan,

> we think about a replicated environment with 1 master and 14(!)
> updatable snapshot sites. We have little experience in replication, but
> our feeling is that this is quite a risky idea.
>
> Does anyone have practical experience with such a number of snapshot
> sites? Is this realistic?

I have only tried it with two sites, but will share my experiences anyway..

If you plan on using replication in a real-time environment then DON'T!

We had major problems because we trusted Oracle's updatable snapshots to be better than they are. You must consider that Oracle locks the entire snapshot on the sites when refreshing, which can cause application hangs while replication is going on. If e.g. a site has been down overnight, and it is a system with lots of updates, this period of time that the site cannot update the time can be very long.

We now use read-only snapshots, and handles updates to the master database using an own created replication mechanism, which works great.

Conclusion: snapshots are great, updatable snapshots are not.

Regards,
Brian

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Brian Rasmusson, Software engineer & analyst        e-mail: br_at_belle.dk
Belle Systems A/S                                   web   : www.belle.dk
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