Re: Oracle 24x7 shops and Patches-Upgrades.

Niall Litchfield wrote on 21/12/2006:

> I still don't see how this approach will deal with the
> typical app I see today with code and objects in the db, code and
objects on
> the middle tier in Java (upgrading that online could be a challenge) and
> with code and objects residing on the (thin) client in the form of
> javascript/cookies/cached .jars/dlls etc.

We are hopeful that we will be able to make use of this feature for our main systems, if it works as we think Tom Kyte described it.

Our architecture consists of client browsers connecting to a Java middle tier, which connects to the Oracle database, executing application PL/SQL packages. The Java middle-tier runs on two load-balanced servers.

The online application upgrade sequence would be:

take down middle-tier Java on server 1;
upgrade the application PL/SQL code on the database; middle-tier Java on server 2 continues to run using the old "edition" of the application PL/SQL;
upgrade middle-tier Java on server 1;
start up middle-tier Java on server 1;
middle-tier Java on server 1 uses the new "edition" of the application PL/SQL;
take down middle-tier Java on server 2;
upgrade middle-tier Java on server 2;
start up middle-tier Java on server 2;
middle-tier Java on server 2 uses the new "edition" of the application PL/SQL. The main caveat I picked up from Tom Kyte's talk was that tables are not "versionable". So if one of our upgrades included a change to a table then the above approach would not work, and we would have to suffer downtime, as currently. This could be mitigated by encouraging table access via views.

Patrick Hurley
Database Administrator
Nominet
http://blog.nominet.org.uk/

--
http://www.freelists.org/webpage/oracle-l