Re: Database Sync doubt

spraveen2001_at_yahoo.com (Praveen) wrote in message news:<98d8ec76.0410142057.69d9dc48_at_posting.google.com>...
> Hi,
>
> Thanks for the response.
>
> > Praveen, your possible solutions depend on some information not
> > posted. Most importantly how current must each database be? And if
> > database A is down should database B and C be available for update or
> > unavailable till A is available again?
>
> Yes in case database A is down, B and C will be available. Can it
> possible like if A is available again, then update A database with
> missing data from B and C. Is there any facility in Oracle?
>
> > If the data must be always in sync then placing a trigger on each
> > table to update the remote instances at the time of DML activity using
> > distribued transactions is one possibility. But if one database is
> > down the entire system is down.
>
> Will it be database operation will slower if, for each DML activity by
> trigger on each and update the remote instances?
>
> > You could use a transaction buffering system to hold local activicy
> > during remote outages and send it when the remote system become
> > available.
>
> Is this transaction buffering system is a facility/feature available
> in Oracle?
>
> > You can also look into master to master (advanced) replication.
> >
> > If some delays in data transmission are acceptable then Oracle's basic
> > replication might be a possiblity as part of the solution.
>
> Cient have WAN connection for their data transmission. In that case
> also there will be big delay in transmission?
>
> is the oracle database replication is best option for this type of
> scenarios?
>
> Thanks,
> Praveen
>
> Mark.Powell_at_eds.com (Mark D Powell) wrote in message news:<2687bb95.0410140543.6dff3828_at_posting.google.com>...

prior notes removed from post
Yes, the use of row level triggers on the tables will impact performance; however, for OLTP single row or small actions this will not be noticable. Note that if you do this manually or via replication that this is still true. The most noticable effect would be on bulk loads (array inserts) where the triggers turn set operations into row level operations.

I was talking about buffering manually, but Oracle advanced replication I believe provides this feature via its journaling option.

Oracle's Advanced Queues could also be used.

There are lots of options and variations. The devil is in the details, and only you are in a position to compare your system exact requirements verse the capabilites each approach/feature of Oracle offers.

HTH -- Mark D Powell -- Received on Fri Oct 15 2004 - 08:27:34 CDT