Public bug summary:
Customer sees high cpu usage while deleting a single system from 5.2 Satellite, and this is reproduced in-house with their db-dump.  E.g., attempting to delete a single system takes 4-6 minutes and top output shows ~100% CPU on oracle. 

General usage stats:

SQL> select count(*) from rhnServer;

  COUNT(*)
----------
      4832

SQL> select count(*) from rhnServerGroup;

  COUNT(*)
----------
       113

SQL> select count(*) from rhnChannel;

  COUNT(*)
----------
      1048

SQL> select count(*) from rhnPackage;

  COUNT(*)
----------
     33692

SQL> select count(*) from rhnServerChannel;
select
  COUNT(*)
----------
     35876

SQL> select count(*) from rhnServerPackage;

  COUNT(*)
----------
   1478795

Based on statspack reports, the following sql function/procs are highlighted -

...
    133.75            1     133.75   89.4     179.98      78,710,070
1604354683
Module: /usr/sbin/httpd
BEGIN   delete_server(:p1); END;

    132.10           16       8.26   88.3     132.10      78,205,269
3381249446
Module: /usr/sbin/httpd
UPDATE RHNPRIVATECHANNELFAMILY SET CURRENT_MEMBERS = ( RHN_CHANN
EL.CHANNEL_FAMILY_CURRENT_MEMBERS(:B1 , :B2 ) ) WHERE ORG_ID = :
B2 AND CHANNEL_FAMILY_ID = :B1

    132.07           16       8.25   88.3     132.07      78,204,755
1641884697
Module: /usr/sbin/httpd
SELECT COUNT(SC.SERVER_ID) FROM RHNCHANNELFAMILYMEMBERS CFM, RHN
SERVERCHANNEL SC, RHNSERVER S WHERE S.ORG_ID = :B2 AND S.ID = SC
.SERVER_ID AND CFM.CHANNEL_FAMILY_ID = :B1 AND CFM.CHANNEL_ID =
SC.CHANNEL_ID AND EXISTS ( SELECT 1 FROM RHNCHANNELFAMILYSERVERP
HYSICAL CFSP WHERE CFSP.CHANNEL_FAMILY_ID = :B1 AND CFSP.SERVER_

...

and possibly
...
      4.90            1       4.90   24.6       4.90       2,884,225 
721418455
SELECT             G.ID AS ID, G.NAME AS NAME,
     (SELECT COUNT(*) FROM rhnUserManagedServerGroups UMSG WHERE
 UMSG.server_group_id = G.id)          AS GROUP_ADMINS,    (SELE
CT COUNT(*) FROM rhnServerGroupMembers SGM WHERE SGM.server_grou
p_id = G.id                  AND EXISTS ( SELECT 1
...

Deleting a system with no channel or group memberships is faster (<20 sec) than otherwise.  Internal reproducer info and more background to follow.