Re: Replication - how hard is it really? (Updatable snapshots..)

The actual preparation of definitions, installation and general mechanical activity is a bit long-winded and fiddly but not too painful, and things shouldn't get too difficult with only two nodes, BUT ...

The main problem is covering all the angles of dealing with 'conflict resolution' - defining rules for ways in which the system should behave when the same record is updated differently at both ends of the system.

Oracle offers several conflict resolution rules to help, but you still have to decide which one applies when, and whether you want to invent some of your own; then you still end up with a lot of hassle when something goes wrong and you have to tidy up.

Personally I always advise fairly strongly against using an asynchronously replicated system on the basis of the high probability of unanticipated situations occurring and the cost of resolving them when they do.

--

Jonathan Lewis
Yet another Oracle-related web site: www.jlcomp.demon.co.uk

mdlcpgs_at_alpha.gns.cri.nz.nospam wrote in message <7k1qac$j2p$1_at_newshost.comnet.co.nz>...
>We are comtemplating setting up replication between 2 Oracle Workgroup
>servers. One is the master, but the other needs updatable copies of some
>of the tables stored at the master. On any day, both the master and the
>remote snapshot could be independently updated. We would hope to
synchronize
>with a new snapshot process every night.
>
>While Oracle says that the server supports multiple updatable snapshots, we
>have been given some warnings by a third party (that might have some axes
to
>grind) that replication is actually fraught with problems and we should
avoid
>at all possible. What are peoples experience of this kind of replication?
>What can go wrong? Does it need constant maintenence or is it just major
>pain to set up? Your experiences please!
Received on Mon Jun 14 1999 - 01:39:22 CDT