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Re: Oracle on multiple sites

From: Pete Sharman <psharman_at_us.oracle.com>
Date: Wed, 16 Jun 1999 09:08:06 -0700
Message-ID: <3767CBE5.7B6046AD@us.oracle.com>


Steve

Here's the 50,000 feet level overview of setting up snapshots.

You need to decide which is your master site, and thus which is your snapshot site. You need to set up the snapshots at the snapshot site using the CREATE SNAPSHOT command, with FOR UPDATE specified for updatable ones. If you can do a fast refresh, you need to create snapshot logs using the CREATE SNAPSHOT LOG command.
You need to define from a business perspective what your conflict resolution method will be (site priority, latest timestamp, etc.). You need to register your conflict resolution method in the database. You need to monitor and manage the environment once it's set up.

All of the setup can be done through replication manager if you don't want to use the API, or alternatively you can use SQL directly. It's not really that complex, but it does need forethought, particularly looking at the business requirements for conflict resolution. If there was no need for update access at both sites, it's more straightforward.

HTH. Pete

Steve-a wrote:

> OH GOD!!
> I thought this would be easy,
> so if i use snapshots, do I have to set them up at both ends? and how
> does the oracle inform you of a possible clash( 2 sites modifying the
> same record,before the snapshot has taken/updated)
> and if the servers are in different time zones , would this be handled
> correctly?, & how do the servers sync the time, because if the clocks
> are not sync'd , it could get really messy.
>
> One last point, do I have to make any special setup for a firewall?
> on my tests i can access the oracle database using a client thru Ip/
> using the server name "micromark.com.cn" which resolves to
> 202.104.30.68, from within my firewall, but on the outside i cannot gain
> access. ( I know that's what firewalls are for),even if i disable the
> firewall I cannot access the oracle when connected from another site,
> using the same client for both tests.
>
> steve
>
> steve
>
> Pete Sharman <psharman_at_us.oracle.com> wrote:
>
> > This is a multi-part message in MIME format.
> > --------------20A4D26CBADA40AD0F55FC26
> > Content-Type: text/plain; charset=us-ascii
> > Content-Transfer-Encoding: 7bit
> >
> > In this case, the snapshot option is OK, but it must be updatable since both
> > sites can update the data locally. As a result, there's a lot more involved
> > than simple snapshots, particularly in the area of determining how to handle
> > conflicts.
> >
> > HTH.
> >
> > Pete
> >
> > Grange Man wrote:
> >
> > > You could use Oracle "snapshots" to do this. Snapshots can update the TARGET
> > > either at intervals, or by 'manual' activation (with a scheduled script or
> > > Oracle "JOB"). The only negative of snapshots is that you must monitor for
> > > their success.
> > >
> > > Snapshots can be set up to grab only the incremental changes to a large
> > > database, so overhead can be small.
> > >
> > > Steve-a wrote:
> > >
> > > > Hi,
> > > > Looking for some advice on linking 2 /3 sites.
> > > >
> > > > Each site has oracle 8 installed.
> > > > The databases are /should be identical, but any updates must be
> > > > replicated to all sites,
> > > > None of the sites would SQL any other of the sites, since the data would
> > > > be held locally and synced by oracle.
> > > > data flow will be Quite small 20/30 records added/modified per day.
> > > >
> > > > Which setup do I need.
> > > >
> > > > steve
> > > >
> >
> > --
> >
> >
> > Regards
> >
> > Pete
> >
> >

--

Regards

Pete


Received on Wed Jun 16 1999 - 11:08:06 CDT

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