Hi All,
I am working on a similar project here. I am wondering if anyone in the list ever compared Oracle Data Guard with iReflect from Data Mirror. Please share your experience with us.
Thanks,
Kitty
-----Original Message-----
Sent: Monday, December 08, 2003 6:54 PM
To: Multiple recipients of list ORACLE-L
Hi Carel,
What if 50% of tables doesn't have Primary/Unique
keys, how it is going be with LSB then? Can you please
explain more.
with thanks,
Vi
- Carel-Jan Engel <cjpengel.dbalert_at_xs4all.nl>
wrote: > Comments inline
>
> At 14:54 8-12-03 -0800, you wrote:
> >Hi Carel,
> >
> >That is good help, can you please send me the pdf
> that
> > you implemented there then.
>
> Was on its way already
>
>
> > Tell me one thing I agree that we some
> >times
> >(rather most of the time ) generate less redo so
> we
> >should be smooth. Can you tell me is there any
> >releation between LSB and Primary keys, I read
> like
> >LCR(logical Change Request) is based on Primary
> keys
> >as It does not depends on Transaction at that time.
>
> Because LSB 'reverse engineers' SQL from the redolog
> info, it needs to get
> hold of the right rows. The rows get
> inserted/updated/deleted, and _a_
> unique identification, not being the rowid, is
> required. So, every row
> needs to be uniquely identified.
>
>
>
> >Have you implemnented LSB successfully?
>
> Yes, using a PSB / LSB combination for standby and
> reporting purposes
> respectively.
>
>
> >with many thanks,
> >Vi.
> >
> > --- Carel-Jan Engel <cjpengel.dbalert_at_xs4all.nl>
> >wrote: > Comments inline
> > >
> > > At 13:34 8-12-03 -0800, you wrote:
> > > >Hi Tanel,
> > > >
> > > >
> > > >Much appreciated, The fact is I am interested
> in
> > > >Logical standby rather than physical.
> > > >
> > > > Our 30-50% of our Production data needs to
> be
> > > >replicated to another database and where they
> will
> > > >have their processing and batches.
> > >
> > > It all depends on the amount of redolog you
> > > generate. When that's pretty
> > > much, you waste some resources by transporting
> > > online/archived redologs you
> > > actually don't need.
> > >
> > >
> > > > Now We didn't go to Snapshot because It is on
> > > >multiple tables (where we didnot have PK's and
> > > many
> > > >tables) and due to performance issue I didn't
> want
> > > to
> > > >use Snapshots (they did not want any tables to
> be
> > > >truncate before being loaded even via
> snapshots).
> > >
> > > So, they don't like nologging operations like
> > > truncate, not even on the
> > > standby database?
> > >
> > >
> > > > The best option I think is Logical Standby
> > > Database.
> > > >Or Can you please suggest me any other means.
> > > >
> > > > Replication should be quicker like
> once
> > > in
> > > >every 20 minutes, Even Transportable tablespacs
> > > does
> > > >not work here since they need all tables to
> 24*7.
> > >
> > > LSB might work, but do not consider the option
> of
> > > failing over to it. Be
> > > aware that, altough in maximum protection mode
> your
> > > redolog arrives at the
> > > SB system within the transaction, it doesn't get
> > > applied there instantly.
> > > SQL Application takes place _after_ the
> log-switch
> > > on the Primary. When you
> > > take 10 minutes of redolog, and perform a
> logswitch,
> > > the SQL Apply process
> > > might even take longer than 10 minutes to
> complete
> > > processing of the
> > > redologfile. There is a risk that not every
> > > transaction arrives within 20
> > > minutes at the LSB. So, your log-switching
> frequency
> > > and the amount of redo
> > > you generate per unit of time both play a major
> role
> > > in the refresh rate of
> > > the LSB.
> > >
> > > I'll send you the PDF of a DG Special I did in
> Kista
> > > a few months ago.
> > >
> > >
> > > Regards, Carel-Jan
> > >
> > > -- There will allwasy be another 10 last bugs --
> > >
> > >
> > > >Any suggestion would be more helpful.
> > > >
> > > >with thanks,
> > > >Vi.
> > > >
> > > >
> > > >
> > > >--- Tanel Poder <tanel.poder.003_at_mail.ee>
> wrote: >
> > > >
> > > >Hi All,
> > > > > >
> > > > > > can any one let me know kindly the
> following
> > > info.
> > > > > >
> > > > > > 1) Has any one used the Oracle 9i Data
> Guard?
> > > > >
> > > > > Yes, physical standby and successfully.
> > > > >
> > > > > > 2) If yes then, is there any performance
> > > impact
> > > > > on
> > > > > > Target/Source server database.
> > > > >
> > > > > Your database has to be in archivelog mode,
> but
> > > when
> > > > > you are thinking such
> > > > > solutions as DG, then you probably are
> already
> > > > > running archivelog anyway.
> > > > >
> > > > > If you run in maximum protection or maximum
> > > > > availability, yes there is. The
> > > > > impact depends mainly on network connection
> > > between
> > > > > primary and standby(s)
> > > > > and the speed of redolog disks. You could
> tune
> > > these
> > > > > by using faster
> > > > > network, enabling jumbo frames and SDU size
> if
> > > using
> > > > > Gbit ethernet, also
> > > > > setting lgwr and log apply processes
> priority
> > > higher
> > > > > than others.
> > > > >
> > > > > > 3) any drawbacks using Data Guard.
> > > > >
> > > > > You should set your database or critical
> > > tablespaces
> > > > > to force logging mode
> > > > > in order to transfer all changes to standby
> in
> > > > > physical standby. That means,
> > > > > performance improvements which take
> advantage of
> > > > > nologging operations (such
> > > > > insert append nologging etc), will not run
> that
> > > fast
> > > > > anymore.
> > > > > In logical standby, I think there's no such
> > > > > requirement, but I don't
>
=== message truncated ===
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Received on Tue Dec 09 2003 - 14:14:33 CST
