A couple of questions in relation to online replication

Hi, guys!

I have a couple of questions in relation to online replication to ask.

We are using Oracle 9i (9.2.0.4) on HP_UX 11i. At the moment, we have two production sites. One is online production site (PROD), another one is the disaster recovery site (DR). We ONLY replicate from PROD to DR. We direct all MIS and read-only sessions to DR site to balance the load while the DR is mainly for real disaster recovery purpose.

Recently, we found two issues with the replication we built 3 months ago.

First, the sequences are not updated by the replication as we expected
(Bear with me, I am newbie). After read more documentation, we found
the sequences are not updated by online replication. The reason makes sense to me: In a real multimaster replication environment, a sequence issues new numbers in each site and then replication across different sites, so sequences should not be included in replication process because we don't want to face continuous data conflictions between sites. So we came up with the simple idea of rebuilding initial DR database with EXP of PROD(using Oracle Advanced Replication Scripts), then changing PROD and DR to use odd interval for PROD sequences and even interval for DR sequences. I think it might be alright for this one.

Then, we found we need to use some of the Oracle Advance Replication scripts to ensure any object changes (except sequences) are replicated. We found our previous replication job between PROD and DR can't push the schema changes in PROD to DR. We ended up with missing columns in some of the DR tables in our recent DR exercise.

Here comes my first question, can I use OEM replication feature ONLY, to build the replication to replicate object changes (sequence is an exception), e.g. new columns, etc.. ? To be honest, I am very sure I can do it because I have done this in UAT, but I just can't exactly remember how I did it at that time and I don't have time to build UAT at DR to test. Anybody with quick answer?

Second question, for the purpose of building one-way replication
(standby site), will it be a good idea to use Oracle Data Guard? I
have just quickly flipped through some of the documents, it seems to be a suitable solution for us. My only concern is how to minimise the latency. Can I use relatively small log files in DR? As you know, I told my boss we have virtually 3 seconds latency in the current replication system. He won't be happy if I tell him now I need 30 mins. Haha!

Well, any input would be appreciated.

Thanks,

Gary Received on Mon Jan 12 2004 - 23:22:18 CST