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 <[EMAIL PROTECTED]> 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 <[EMAIL PROTECTED]> > >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 <[EMAIL PROTECTED]> > 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 === ________________________________________________________________________ BT Yahoo! Broadband - Save £80 when you order online today. Hurry! Offer ends 21st December 2003. 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