In my earlier post, dated 27-Sept-2011, I shared how we were able to resolve the issue of Cursor Pin S Waits and 100 % CPU.
1. Apply patch 6904068
2. Set _first_spare_parameter = 1 (keep increasing this value slowly if the problem still exists, do not set it very high as this can worsen things)
We generally apply the Oracle Quarterly PSU Patches within a month of their release. Patch 13343471 (PSU 10.2.0.5.6 for January 2012) was applied, which conflicted with the earlier applied patch to fix the High CPU usage when there are "cursor: pin S" waits, and rolled it back.
The following day, we saw the bug hit again, on two of our databases. We immediately got in touch with Oracle Support, and found out that there's another patch -- Bug 13619396: MERGE REQUEST ON TOP OF 10.2.0.5.6 PSU FOR BUGS 6904068 7045446 8684595.
Beware, the _first_spare_parameter that we had set when we initially set is not applicable after applying the updated Bug Fix. Instead, you have to set _third_spare_parameter.
Hope this helps, as there is no mention of this on the internet as yet.
