This is MY Sticky Note about installation of patchset 10.2.0.5 on Windows x64 (single instance, no database vault), followed by Patch 2 installation. Make sure you read README.html that comes with Patchset, this sticky note is MY note and as such is not a substitute for README.html.

-- Make a backup of database, Oracle Software (ORACLE_HOME) and Oracle inventory
-- Install Patchset 10.2.0.5 binaries.

sql> connect / as sysdba
sql> startup upgrade
sql> spool utlu102i.log
sql> @?\rdbms\admin\utlu102i.sql
sql> spool off

I got two warnings:

**********************************************************************
Update Parameters: [Update Oracle Database 10.2 init.ora or spfile]
**********************************************************************
WARNING: --> "shared_pool_size" needs to be increased to at least 201326592
WARNING: --> "java_pool_size" needs to be increased to at least 67108864

sql> shutdown immedite

< fix the problem >

sql> startup upgrade
sql> spool patchset_10205.log
sql> @?\rdbms\admin\catupgrd.sql
sql> spool off

sql> shutdown immediate
sql> startup

sql> @?\rdbms\admin\utlrp.sql

-- check status of components:

set lines 100
column comp_name format a40
column version format a20
column status format a20
SELECT COMP_NAME, VERSION, STATUS FROM SYS.DBA_REGISTRY;

-- RMAN catalog upgrade (if the RMAN catalog is not yet at >= 10.2.0.5)

rman catalog rman/rman@tns
rman> upgrade catalog;

Because of the bug introduced with patchset 10.2.0.5 I postponed deployment of patchset 10.2.0.5 until Oracle released a fix in Patch 1 in mid September 2010, then I saw that Patch 2 (which is also a security bundle CPU October 2010) is planned for mid October 2010 and decided to wait for Patch 2 rather than installing Patch 1.

--
-- MY sticky note for installing Patch 2 on top of 10.2.0.5
-- Again, reading README.HTML is MANDATORY!
-- Download patch# 10155844 (p10155844_10205_MSWIN-x86-64.zip) and 
-- Opatch 10.2.0.5, patch# 6880880 (p6880880_102000_MSWIN-x86-64.zip).
-- Follow instructions in readme for Opatch installation.
--  Patch 2 archive unzip in some temporary directory 
-- (my location of choice was D:\ORACLE\10205_Patch2)
1) Backup database
2) Backup Oracle inventory (C:\Program Files\Oracle\...)
3) shutdown immediate
4) net stop OracleServiceSID
5) net stop OracleORA10TNSListener
6) net stop "Distributed Transaction Coordinator"
7) cd D:\Oracle\10205_Patch2\10155844
8) set PATH=D:\ORACLE\ORA10\Opatch;%PATH%
9) opatch lsinventory
10) opatch apply
11) check log file (D:\ORACLE\ORA10\cfgtoollogs\opatch)
-- post installation steps
12) net start OracleServiceSID
13) cd D:\ORACLE\ORA10\BUNDLE\Patch2
14) sqlplus /nolog
15) connect / as sysdba
16) startup     
17) @catcpu.sql
18) quit
19) check log file (D:\ORACLE\ORA10\cfgtoollogs\catBundle)
20) you can check REGISTRY$HISTORY for Patch 2 installation note
21) optioanl: if catcpu.sql reports invalid objects run utlprp.sql
22) net start OracleORA10TNSListener
23) net start "Distributed Transaction Coordinator"

Everything went smooth during 5 test and one production installment, more are on the way during this week. I’m happy to report that trace files reporting “WARNING:Could not lower the asynch I/O limit” are gone.