Common Problems when we observe package cache increasing a lot are erros in db2diag.log such as:

    PID     : 31135                TID  : 2200449313104PROC : db2sysc 0
INSTANCE: db2inst1             NODE : 000         DB   : MNTTBPP
APPHDL  : 0-1910               APPID: 10.210.51.24.50193.091207012503
AUTHID  : USRMNT 
EDUID   : 81                   EDUNAME: db2agent (MNTTBPP) 0
FUNCTION: DB2 UDB, common communication, sqlcctcptest, probe:11
MESSAGE : Detected client termination
DATA #1 : Hexdump, 2 bytes
0x0000020054FF5CF2 : 00

2009-12-06-23.25.15.193826-120 I24828083A524      LEVEL: Error
PID     : 31135                TID  : 2200449313104PROC : db2sysc 0
INSTANCE: db2inst1             NODE : 000         DB   : MNTTBPP
APPHDL  : 0-1910               APPID: 10.210.51.24.50193.091207012503
AUTHID  : USRMNT 
EDUID   : 81                   EDUNAME: db2agent (MNTTBPP) 0
FUNCTION: DB2 UDB, common communication, sqlcctest, probe:50
MESSAGE : sqlcctest RC
DATA #1 : Hexdump, 2 bytes
0x0000020054FF5DD0 : 0036

To temporarily fix you have to schedule the command below:

db2 FLUSH PACKAGE CACHE DYNAMIC

To permanent fix apply the special fixpack below:

http://www-01.ibm.com/support/docview.wss?uid=swg1LI74522