Describe Oracle Patches

Regarding to Oracle Documentation patch is program (set of instructions) to fix a particular problem or enhance/ add a particular feature in existing program/product/software. And There’s Four kind of Oracle Patches :

  • One-off patches (bug fix)
  • CPU (security patches)
  • Upgrade patches (bug fixes)
  • PSU (bug fixes are security patches)

There’s another kind called Bundle Patched for windows and exadata.
The most two kind of patch that people get little confused about them is CPU and PSU what are they ? when should i use them ?  is there any different between them ?

First Thing you need to know about them since they have different name then sure it’s have different.

CPU:  security fixes each quarter rather than the cumulative database.

PSU : same as CPU  patches but include both the security fixes and priority fixes.Note Once a PSU is applied, only PSUs can be applied in future quarters until the database is upgraded to a new base version.
Which mean you can’t Apply CPU and PSU and same database.

Some MOS note that could be Useful :

Introduction to Oracle Patch Set Updates (PSU) 854428.1
Quick Reference to Patchset Patch Numbers [ID 753736.1]
Quick Reference to Patch Numbers for Database PSU, SPU(CPU), Bundle Patches and Patchsets [ID 1454618.1]
New Patch Nomenclature for Oracle Products [ID 1430923.1]

PSU  contain fix for bugs that cause Instance crash,Wrong results and Data Corruption on the other hand Dictionary changes , Major Algorithm changes ,and Optimizer plan changes not fixed by PSU.

to check Applied PSU patched you need to run :

opatch lsinventory -bugs_fixed | grep -i ‘DATABASE PSU’

 and if you need to check CPU :

 Select * from registry$history;

Thank you
Osama mustafa

Applying Critical Patch Updates (CPU).

A Critical Patch Update is a collection of patches for multiple security vulnerabilities. Critical Patch Update patches are usually cumulative but each advisory describes only the security fixes added since the previous Critical Patch Update advisory. Thus, prior Critical Patch Update advisories should be reviewed for information regarding earlier published security fixes.its released on January, April, July &October.

Steps to Apply CPU: 

Pre-Installation:

  1. Shutdown all the instance , and oracle services such as listener. 
  2. ensure $PATH variable.
  3. Download Patchand unzip it.
  4. Use the Opatch like this : opatch napply -skip_subset -skip_duplicate.
  5. Startup databas.

Post-Installation :

  1.  cd $ORACLE_HOME/rdbms/admin
  2. sqlplus / as sysdba
  3. SQL> @catbundle.sql cpu apply
     
     

     

Note : For rac database nothing diffrenece unless you have to shutdown services node by node and patching ( you can patch one node then the other one).

Useful MOS notes :
Introduction To Oracle Database catbundle.sql [ID 605795.1]

 Thank you 
Osama Mustafa