Reliable Patching Info in 11i

Question

How can I determine whether or not a patch or bug has been installed? Here's the problem... We are running 11.5.10.2 and according to OAM, patch #4645189 has NOT been installed however a query of ad_bugs shows that it HAS been installed.
Also, running this script:
select decode(p.patch_name, 'merged', substr(d.driver_file_name, 2,7),
'mergeDB', substr(d.driver_file_name, 2,7),
'WRONG_DRIVER', substr(d.driver_file_name, 1,8), p.patch_name) "Patch Name",
d.driver_file_name "Driver File", d.orig_patch_name, r.start_date, r.end_date,
--trunc(end_date-start_date) "Days",
lpad(to_char(trunc( 24 * ( ((end_date-start_date) - trunc(end_date-start_date)) )) ), 2, '0')
|| ':' || lpad(to_char(trunc(60 * ( ((end_date-start_date) * 24) - (trunc((end_date-start_date) * 24)) )) ), 2, '0')
|| ':' || lpad(to_char(round(60 * ( ((end_date-start_date) * 1440) - (trunc((end_date-start_date) * 1440)) )) ), 2, '0') "Elapsed Time"
from applsys.ad_patch_runs r, applsys.ad_patch_drivers d, applsys.ad_applied_patches p
where r.patch_driver_id = d.patch_driver_id
and p.patch_name ='&Patch_Number'
and d.applied_patch_id = p.applied_patch_id
--and trunc(start_date) > '19-JAN-03'
order by r.start_date
Shows that the patch was NOT installed. Using the Oracle pkg, is_patch_applied shows that patch has been applied.
Which is the best method to determine if a patch or bug has been applied to the system?
What is the difference btwx ad_bugs and ad_applied_patch?

Answer 1

The bug 4645189 was not listed in the readme for the patch (5310177). Nor in any of the patches that I drill into.
That is expected because Patch 4645189 is not included in any other patch.
Is it possible to check the patch create/update date from ad_bugs table? Maybe we could reach something if you find the list of patches that were applied at that time. You may also try to search OAM for Patch 4645189 using this date.