Logical standby does have greater flexibility than a physical standby when it
comes to diverging data. You can use the LOGSTDBY package with the SKIP
function to prevent certain statements from being replicated. In table 97-23
here
https://docs.oracle.com/en/database/oracle/oracle-database/18/arpls/DBMS_LOGSTDBY.html
It looks like there is an option to use the SKIP function of DBMS_LOGSTDBY to
not propagate both a TRUNCATE TABLE statement and regular DML statements. I did
a short-lived project with this three years ago, that ended up being overturned
shortly after we had it running in production. We didn’t use the truncate part
of it but did skip DML for a certain table so that the standby could have that
table be unique (different configs for the app on the standby side of things).
Of course, there are all kinds of dangers about having divergent data and
systems, so whether or not a standby where some things are skipped is a good
solution is entirely dependent on the use case.
Thanks,
Ross
From: <oracle-l-bounce@xxxxxxxxxxxxx> on behalf of Mladen Gogala
<gogala.mladen@xxxxxxxxx>
Reply-To: "gogala.mladen@xxxxxxxxx" <gogala.mladen@xxxxxxxxx>
Date: Monday, December 16, 2019 at 4:47 PM
To: oracle-l <oracle-l@xxxxxxxxxxxxx>
Subject: Strange developer ideas
CAUTION: This email originated from outside of the organization. Do not click
links or open attachments unless you recognize the sender and know the content
is safe.
i've got a request from a developer to use logical standby as a DW
database. The idea is that "DELETE" and "TRUNCATE" commands on the
primary shouldn't be propagated to the standby. I told her that such
thing can only be done by using the Force, not the normal Oracle tools.
I sent this as an argument:
https://urldefense.com/v3/__https://asktom.oracle.com/pls/apex/f?p=100:11:0::::P11_QUESTION_ID:22699268606133__;!!N4fOi5Mv!KVt2_0hx0eyq0YKGe4GqOEVtGxtMs2doU7pTYuS_vdgXTsgHihmdAqBPntn41Q_PWrY$<https://urldefense.com/v3/__https:/asktom.oracle.com/pls/apex/f?p=100:11:0::::P11_QUESTION_ID:22699268606133__;!!N4fOi5Mv!KVt2_0hx0eyq0YKGe4GqOEVtGxtMs2doU7pTYuS_vdgXTsgHihmdAqBPntn41Q_PWrY$>
Now, the PM in charge of the project on which the aforementioned
programmer is working sent me nastygram, accusing me of stalling and
obstructing their project and colluding with Russians. I dared
suggesting purchasing the Golden Gate license, which is completely
capable of performing the required operation, but it wasn't interpreted
as a helpful suggestion.
Just to cover all my angles, is anything like that possible with the
logical standby? Has anyone managed to do anything like that? I have
always considered standby a copy of the primary. Calling all Force users
on this group, especially the ones dabbling in the Dark Side.
--
Mladen Gogala
Database Consultant
Tel: (347) 321-1217
--
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