I will lay down in the log my experience in building a AWR warehouse. Experiences I believe being potenially useful for other Oracle users.
I will write a no general introduction into the ARW warehouse. To find out what it is and why you need it, I would, for example, refer to the blog of Kellyn Pot’Vin Gorman: http://dbakevlar.com/2014/06/awr-warehouse-in-em12c-rel-4/.
Day 1 (12.24.2014)
When the databases are linked with the AWR warehouse , PL / SQL code is installed in the user DBSNMP. In some databases we encountered compiling errors.
We found that these databases were hardened . That means all rights not currently needed are revoked from users . We had to assign the following rights to user DBSNMP:
grant execute on utl_file to dbsnmp;
grant execute on DBMS_RANDOM to dbsnmp;
grant execute on DBMS_SCHEDULER to dbsnmp;
The rights to the databases in the AWR warehouse we granted over SSH. For a single node database it was issue free, at a cluster database the option was not offered. The reason is an error in the GUI to be corrected in the next patch. For the time being you can use EMCLI as a workaround.
Speaking EMCLI. The adminstration of the AWR warehouse via EMCLI is only partialy possible. This should also change with the next patch due in December 2014.