Confusion about Oracle Patches?

Whenever a bug is being detected and confirmed for fix, Oracle engineers raise a request for bug engineers / development to provide a patch for customer. There are different types of patch requests in order to fix the issue while making sure not to disturb already existing patch in the target environment. Few patches/patchsets are proactively recommended for security, stability, performance and environmental changes (i.e. DST) perspective.

Whenever someone asks me regarding patching I used to confuse a lot and read oracle documentation every time. When the question came again the same level of confusion appear pushing me into loop of reading and forgetting the concepts of patch terminologies. So this time I have decided to share my understanding so it would be easy to recall and enhance based on feedbacks and queries.

When a bug is detected in UNIX, the patch fix for this bug is given via object files. These object files have an extension of “.o” . These “.o” files are stored in an “archive library”. The patch contains Static Libraries and Shared Libraries. The Executables are generated using static libraries and linked using shared libraries. These Executables are generated on the fly in oracle binary, where the patch is being applied.

Whereas, in Windows there is no concept of “.o” files at all. There are only DLL’s (Dynamic Linked Libraries) and Executables in the library. The difference is that these Executables are generated at the patch shipment site, and not in the machine where patching to be done. So when customer applies a patch fix, the Oracle Executables those already exist in the target Oracle Home will be replaced with Oracle Executables from the patch. This action results in the older patch fix to be lost. This nature of patch applying in Windows makes it impossible to create individual patches for bug fixes. Instead, many patches are clubbed together and a “bundle patch” is released. All the Bundle patches in Windows are cumulative in a particular release. It means that fixes from previous Oracle security alerts and bundle patches are included.

Before jumping to types of patches/patchsets, let’s understand few terminologies related to patch.

Label – For internal references Oracle developers use a name or identifier for a set of changes (e.g. the fixing of a bug) in the source code; the output of a label is a set of C files (*.c, *.h etc)