Oracle R12 Upgrade from 11i and Database Versions

here is some information on R12 Upgrade process. This Upgrade post revolves around Database version with Oracle Applications (E-Business Suite)

Key points to note in Oracle Apps R12 upgrade from 11i
– R 12 upgrade process involve replacing 11i Tech stack (9iAS & 806) to Fusion Middleware (10g Application Server)
– Basic upgrade process involves Rapid Install & Autopatch
– Rapid Install involves installing new R12 tech stack as mentioned in first point
– Auto patch process involves upgrading E-Business Suite database compatible to R12 (Data Model)
– Final upgrade process is of updating data model using enhanced version of AutoPatch
– Minimum version from which you can upgrade to R12 is 11.5.7 and higher
– Minimum database version from which you can upgrade to R12 is 9i
so if your database is still 8i or <>
– Database must be 10.2.0.2 before or during upgrade process & prior to running AutoPatch which will upgrade datamodel to R12 As per Oracle R12 Upgrade Documentation, Apps 11i Instance is classified in Two Categories based on Apps & DB Version
Category 1 - 11.5.7, 11.5.8, 11.5.9 (CU1), 11.5.10 (CU1)
Category 2 - 11.5.9 (CU2), 11.5.10 (CU2) or 11.5.10.2For Category 1 , database should be upgraded during R12 upgrade process (Downtime for R12 upgrade process will be more as this involve database upgrade as well) but for Category 2 Database can be upgraded before R12 upgrade .Why can’t I upgrade database to 10.2.0.2 before for category 1 ?
This is because there is no Interoperability patch for above release & 10.2.0.2 was supported for 11.5.9 (CU2) & 11.5.10(CU2) only . (Wish I could be on 11.5.10.2 )What are advantages of Upgrading database to 10.2.0.2 before R12 upgrade ?Downtime can be broken down to two small downtimes (one for Database upgrade another one for R12 upgrade) and can be achieved during weekends or long weekends (depending on your system & resources)Various upgrade paths (mainly 3) revolves around application version & database version (mainly on database version).Path A for apps R12 Upgrade :
These are for instances where database is not 10.2 & DB is upgraded during R12 Upgrade
Install the R12 Technology Stack and 10.2.0.2 Oracle home
Upgrade the Database to 10.2.0.2
Perform Database Steps
Complete the R12 upgradePath B for apps R12 Upgrade :
These are for instances 11.5.9.2 & 11.5.10.2 and database is 10.2
Install the R12 Technology Stack and 10.2.0.2 Oracle home
Perform Database Steps
Complete the R12 upgradePath C for apps R12 Upgrade :
These are for instances 11.5.9.2 & 11.5.10.2 and database is NOT 10.2, Here upgrade database first to 10.2.
Upgrade database to 10.2.0.2
Use 11i with 10.2.0.2 DB & then in next downtime window
Perform Database Steps
Complete the R12 upgrade

Related :
For full Steps follow metalink Note # 403339.1 Oracle 10gR2 Database Preparation Guidelines for an E-Business Suite Release 12 Upgrade
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Source :- http://onlineappsdba.com/index.php/2007/01/25/oracle-r12-upgrade-from-11i-database-versions/
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