update-pkgcache.py is swaping

The update-pkgcache.py script is swaping and pushing ackee into swap alert

In this swap usage top update-pkgcache.py is PID 4931

top - 19:06:10 up 166 days, 11:58, 1 user, load average: 2.47, 2.33, 2.36
Tasks: 241 total, 4 running, 237 sleeping, 0 stopped, 0 zombie
Cpu(s): 40.4%us, 1.4%sy, 6.7%ni, 50.9%id, 0.5%wa, 0.0%hi, 0.2%si, 0.0%st
Mem: 6112672k total, 3624624k used, 2488048k free, 40420k buffers
Swap: 2964472k total, 810956k used, 2153516k free, 259048k cached

  PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ SWAP COMMAND
 4931 launchpa 20 0 1403m 476m 2572 S 37 8.0 192:57.45 927m python2.6
11262 bzrsyncd 20 0 606m 243m 6044 S 0 4.1 0:32.00 363m [celeryd@ackee:
30659 launchpa 36 16 582m 229m 3660 R 57 3.8 26:02.23 353m python2.6
19485 rabbitmq 20 0 705m 383m 1788 S 1 6.4 81:39.91 321m beam.smp
11245 bzrsyncd 20 0 414m 102m 7620 S 0 1.7 0:04.33 312m [celeryd@ackee:
 7264 bzrsyncd 20 0 313m 9740 2784 S 0 0.2 0:02.48 304m [celerybeat] --
11260 bzrsyncd 20 0 695m 394m 6000 S 0 6.6 0:48.10 300m [celeryd@ackee:
11261 bzrsyncd 20 0 513m 213m 6068 S 0 3.6 0:12.80 299m [celeryd@ackee:
19723 bzrsyncd 20 0 474m 186m 9580 S 57 3.1 0:07.87 287m python2.6
19720 bzrsyncd 20 0 474m 186m 9584 S 64 3.1 0:08.10 287m python2.6