Patching your Oracle database – Critical Patch Update (CPU) or Patch Set Update (PSU)
Keeping your Oracle database software up to date is a critical and time-consuming task for DBAs. For many years now, Oracle has been releasing Critical Patch Updates on a quarterly basis. These patches, as the name implies, contain critical updates to the software, often released in response to a newly found security vulnerability. More recently, Oracle has also been releasing Patch Set Updates on a quarterly basis. These also contain important fixes to the Oracle software. However, there is confusion about the difference between the two and more importantly, confusion about which one needs to be applied. So whats the difference and which one should you apply? According to Oracle Support article ID 1446582.1: Frequently Asked Questions (FAQ) Patching Oracle Database Server : “A PSU is a collection of proactive, stabilizing cumulative patches for a particular product version (base release or patch set). ...