Applying patches - minimizing database down time

Attention all installation gurus/hacks...

I'm looking for suggestions, experiences, and best practices on safely applying Oracle patches and minimizing database down time. By way of example let's say we're going from server version 8.1.6.0.0 to 8.1.6.3.0. Let's also say we're going to apply the 8.1.6.3.0 interMedia patchset. Here are some generalized steps:

1. Uncompress/untar the patchsets to a staging area.
2. Whilst the database is up, run the installer to install all the requisite software to a new $ORACLE_HOME. old $ORACLE_HOME = /u01/app/oracle/product/8.1.6 new $ORACLE_HOME = /u01/app/oracle/product/8.1.6.3.0 export ORACLE_HOME=/u01/app/oracle/product/8.1.6.3.0 /u01/app/oracle/product/8.1.6/bin/runInstaller
3. Whilst the database is up, copy interMedia executables and libraries to the appropriate sub-directores of the new $ORACLE_HOME.
4. Whilst the database is up, run the installer to install the new patches pointing it to the staging area in step 1.
5. Shut everything down. Shutdown Oracle dependent processes like ctxsrv. Shutdown the listener. Shutdown the database: alter system checkpoint; shutdown abort; startup; shutdown immediate; Do not make any cold backups. Depend on RMAN backups for recovery should anything go awry.
6. Relink oracle. make -f ins_rdbms.mk ioracle
7. Change the PATH and oratab to reflect the new $ORACLE_HOME.
8. Startup the database, listener, and ctxsrv to make the application available.
9. With everything up, run the SQL scripts to complete the patch:
   @catalog.sql
   @catproc.sql
   @catrep.sql
   create or replace java system;
   • interMedia stuff
     @dr0pkh.sql
     @dr0plb.sql
     @dr0type.plb
     
10. scan/recompile invalid objects.

HERE'S THE PIVOTAL ISSUE...
Depending on resources step 9 could take about two hours. What are the effects of executing this while the application is running? Comments and suggestions?

TIA,
Steve Orr

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Author: Steve Orr
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