Patch Terminology

Patch Terminology

Critical Patch Update (CPU):

CPU patch are released quarterly and only includes security-related fixes.
CPUs are usually cumulative, so a later CPU will contain all of the fixes from an earlier CPU for the same patchset.
CPUs are “molecular” which means groups of related fixes (“molecules”) can be excluded if they conflict with existing patches.

Patch Set Updates (PSU):

PSU contains critical bug fixes for its intended patchset and also security fixes.
PSU are cumulative, so they contain all fixes from previous PSUs for the same patchset – they also include the CPU released on the same date. So for example PSUApr2010 includes CPUApr2010.
PSU will increment the last digit of the release number. e.g., to

Security Patch Update (SPU):

Security Patch Update (SPU) terminology is introduced in the October 2012 Critical Patch Update as the term for the quarterly security patch.
SPU patches are the same as previous CPU patches, just a new name.

Bundle Patches:

Bundle Patches are the quarterly patches for Windows and Exadata which include both the quarterly security patches as well as recommended fixes.


The name 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)


Two or more bugfixes which modify the same source code files; if this is the case then only one can be applied, otherwise the code for the fixes will need to be “merged” to produce a new label

Interim Patch:

This is the official name for a one-off patch. Single bug fix.

Merge Patch:

This is combination of labels; if for example you have two bugfixes which touch the same files then you would need to have those fixes merged together, producing one new patch with a new label

Overlay Patch:

When a one-off interim patch conflicts with a PSU, an overlay patch is required. This is basically a merge of the patch you want and the PSU.

Overlay PSU:

During the lifecycle of a patchset, PSUs will normally be released every quarter.
As the patchset reaches maturity it would be expected that there are less critical bugs which can be considered as candidates for inclusion in PSUs.
At some point the number of bug fixes included in each PSU will reach a low enough number that it is no longer considered worthwhile to make the PSU cumulative.
At this point the previous PSU becomes a baseline and all future PSUs are released as “overlay PSUs”.

An example of this is which is the last base PSU for the patchset.
From all PSUs are overlay PSUs, which means that in order to install, for example,, the user must first install and then install on top.
The overlay PSU is cumulative down to the base PSU, which means that by installing the user automatically gets all of the fixes in and below,
then by installing all of the fixes in down to are also included.
If a conflict were to occur between an interim patch and the overlay PSU then a merge of the overlay PSU would be required.
For example, if patch 999999 conflicted with then the user would install as usual and then require a merge overlay patch of merged with 999999.

New Patch Nomenclature for Oracle Products [ID 1430923.1]

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