Re: Data Guard and nologging

Comments embedded

On Fri, 06 Apr 2007 21:14:56 GMT, Chuck
<skilover_nospam_at_bluebottle.com> wrote:

>Oracle says that putting a table into nologging mode on the primary
>database in a data guard configuration can invalidate the standby.
This is why Oracle recommends to enable force logging for the primary. This circumvents the impact of nologging.

 If I
>understand DG correctly, it's just a database that's perpetually in
>recovery mode until activated. Suppose you have a few tables that get
>truncated and rebuilt every time they are used, and there are no foreign
>key constraints involved, will that harm the standby database?

The issue here is that *some* operations won't be logged. TRUNCATE will.
Anything in *direct* mode won't be logged, everything else will. Consistency anyone?
>Obviously no DML would get pushed to the standby,
This is not true. Only DML in *direct* mode will not be pushed to the standby, the rest will. You need to understand the impact of NOLOGGING. You seem to live in the misapprehension NOLOGGING means NOTHING will be logged. This is not correct.

 but if the tables are
>truncated and rebuilt every time they're used, who cares?
>
>Assume that in this case global temporary tables cannot be used. (The
>app that uses them is not single threaded or in a single session.)

GTTs generate no redo. Not using them for your purpose seems to be ill advised.

-- 

Sybrand Bakker
Senior Oracle DBA