RE: logical standby

the real problem is that I'm not going to get enought disk to duplicate the primary, even temporarily.

the one time we tried to use streams before was less than a stellar success.

caught between Scylla and Charybdis again.

-----Original Message-----
From: Mark Bole [mailto:makbo_at_pacbell.net] Sent: Wednesday, September 14, 2005 10:20 AM To: Adams, Matthew (GE Consumer & Industrial) Cc: oracle-l_at_freelists.org
Subject: Re: logical standby

Adams, Matthew (GE Consumer & Industrial) wrote:

> I'm in the process of setting up a logical standby databases that will only have a
> small portion of the tables in the primary database. (due to disk space constraints).
>
> Oracle 9.2.0.5 on Solaris 8
>
> This is my general plan of attack.
>
>
> 1) create a new empty DB to act as the standby
> 2) create that tablesapces that will contain the objects we need.
> 3) run DDL to create empty copies of tables/indexes we want
> 4) reboot primary to turn on parameters needed for Dataguard
> 5) shutdown logical standby and restart it, identifying it as a logical standby
> 6) run the DBMS_LOGSTDBY.INSTANTIATE_TABLE routine for all tables we want
>
> I would appreciate comments on the feasiblity of this approach from anyone that has tried it before.
>

I'm pretty sure that will not work. To have a logical standby you need to build the logminer dictionary on the primary (DBMS_LOGSTDBY.BUILD) and have it shipped to the standby via SQL Apply (archived redo logs). The standby must already exist as a hot backup of the primary.

Two choices:

1. stick with your original plan, but call it Streams-based replication of individual tables and implement it as such.
2. build a true logical standby (assuming you can temporarily get enough disk space), then use the DBMS_LOGSTDBY.SKIP procedure to skip the schemas and tables you don't want, and bypass the guard temporarily to drop all the extra stuff (including tablespaces) that you don't have room for.

I have done something very similar to (2) on the same platform as yours   and am confident that after a few practice runs, it can work for you.

-- 
Mark Bole
http://www.bincomputing.com



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