Why should we apply patch set?

At least for us, it is not really necessary to apply every latest Oracle patch set on our databases unless we really need them. After knowing about the release of patch set from Laurent and Mr.Doug's blogs, I thought of reading a metalink note that describes the list of bugs/issues fixed by this patch set. (ML Note : 401436.1).

While reading the note, following bug fixes really caught my attention:

- SYSTEM RESET of an spfile parameter can corrupt the SPFILE
- /*append parallel*/ can corrupt an index

-deadlock hang on "cursor: pin S wait on X" (typically from DBMS_STATS)

I have come across of many DBAs complaing about this behavior. Few links:


I am really interested in the following bugs fix:

+ Higher CPU / Higher "cache buffer chains" latch gets / Higher "consistent gets" after truncate/Rebuild.

Jonathan Lewis and others have talked about this bug at their respective blogs


Few other bugs fixed in this patch set:
+ Wrong results with bind variables/CURSOR_SHARING
5079978 High US enqueue contention in RAC
5387030 Automatic tuning of undo_retention causes unusual extra space allocation
5439554 "buffer busy wait" timeouts with automatic undo management and in memory undo
5442919 Expired extents not being reused (ORA-30036)
5512921 Instance crash caused by SMON OERI[kcblus_1] / dump

It been really a long list of bugs fixed in this patch set. From my personal experience prospective, I would say, first study the bugs fixed in the patch set before applying on a production database. If all resolving majority of your issues.

Happy reading,