Re: Replication Advice Needed
- From: Carel-Jan Engel <cjpengel.dbalert@xxxxxxxxx>
- To: ranko.mosic@xxxxxxxxx
- Date: Fri, 23 Sep 2005 21:43:07 +0200
I think a warning for streams is appropriate in this case. Following the
plain advice 'go with streams' might give unexpected/unwanted results,
when no proper trade-off of pros and cons is made.
Streams requires supplemental logging. This means that all transactions
at your source database will write extra logging.
When the source database is generating a lot of redo already, that might
be an unwanted side effect, expecially because only 5 tables need to be
replicated.
The advantage of 'Old, Proven Technology' of AR might outweigh the
advantage of 'New Technology with Supplemental Logging', especially in
your case, where the extra overhead of AR will lean on the 5 tables
only, where supplemental logging will lean on the whole database.
My advice: test the effects of Supplemental Logging carefully, for your
day-to-day business as well as large batches run at lower frequency,
before making irrevertable choices. Extra redolog from day to day can
force you to allocate extra storage for the archives, and can also
change the time to recover after a restore, due to the extra amount of
archives to be recovered/applied. Maybe it insignificant in your
situation, but test it first.
Best regards,
Carel-Jan Engel
===
If you think education is expensive, try ignorance. (Derek Bok)
===
On Fri, 2005-09-23 at 15:19 -0400, Ranko Mosic wrote:
> Go with Streams. It works quite well. It is also faster than AR, and
> easier to setup.
> For initial setup check Sanjay Mishra's
> http://www.oracle.com/technology/oramag/oracle/04-nov/o64streams.html
>
> Ranko.
>
>
<SNIP>
> >
> >
> >
> >
> > -----Original Message-----
> > From: oracle-l-bounce@xxxxxxxxxxxxx on behalf of Charlotte
> Hammond
> > Sent: Fri 9/23/2005 10:55 AM
> > To: ORACLE-L
> > Subject: Replication Advice Needed
> >
> > Hi All,
> >
> > We need to keep 5 (small-ish / low-volume) tables on a
> > remote database in sync with those in the local
> > database. We want synchronous updates of the remote
> > tables when the network allows but we also want to
> > apply queued transactions after recovery from a
> > network failure such that no transactions are ever
> > lost (assuming the local database to be "unbreakable"
> > :-)
> >
> > I'm thinking of advanced replication or streams but
> > unfortunately I don't have any experience in either.
> > I know this is going to require lots of reading and
> > experimenting but I was hoping to short-circuit this
> > by at least focusing on the right technology to start
> > with!: what sounds like the best fit - AR or streams?
> > (This is on 10g)
> >
> > Thank you all in advance for any help
> >
> > Charlotte
> >
> >
> >
> >
> >
> > __________________________________
> > Yahoo! Mail - PC Magazine Editors' Choice 2005
> > http://mail.yahoo.com
> > --
> > //www.freelists.org/webpage/oracle-l
> >
> >
> >
> >
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