Too many postgres instances

Hi,

Can anyone explain to me why my system is spawn so many postgress instances?
System: FreeBSD 7.2 Stable I386
RAM: < 1GB

Here is the output of the top command:
Mem: 457M Active, 92M Inact, 150M Wired, 23M Cache, 85M Buf, 18M Free
Swap: 999M Total, 150M Used, 849M Free, 14% Inuse

Here is a list of the postgres instances running in my system:
pgsql 70502 0.0 0.5 10364 3800 ?? Ss 2:24AM 0:28.85
postgres: stats collector process (postgres)
pgsql 70797 0.0 0.4 49724 2892 ?? Is 2:28AM 0:00.24
postgres: liferay lportal 127.0.0.1(54110) (postgres)
pgsql 70798 0.0 0.7 49724 5060 ?? Is 2:28AM 0:00.43
postgres: liferay lportal 127.0.0.1(52754) (postgres)
pgsql 70799 0.0 0.0 49724 0 ?? IWs - 0:00.00
postgres: liferay lportal 127.0.0.1(49593) (postgres)
pgsql 70800 0.0 0.0 49724 0 ?? IWs - 0:00.00
postgres: liferay lportal 127.0.0.1(55760) (postgres)
pgsql 70801 0.0 0.6 49724 5016 ?? Is 2:28AM 0:00.56
postgres: liferay lportal 127.0.0.1(56710) (postgres)
pgsql 70802 0.0 0.0 49724 0 ?? IWs - 0:00.00
postgres: liferay lportal 127.0.0.1(65367) (postgres)
pgsql 70803 0.0 0.6 49724 4508 ?? Is 2:28AM 0:00.27
postgres: liferay lportal 127.0.0.1(55101) (postgres)
pgsql 70804 0.0 0.0 49724 0 ?? IWs - 0:00.00
postgres: liferay lportal 127.0.0.1(62522) (postgres)
pgsql 70805 0.0 0.0 49724 0 ?? IWs - 0:00.00
postgres: liferay lportal 127.0.0.1(57897) (postgres)
pgsql 70806 0.0 0.0 49724 0 ?? IWs - 0:00.00
postgres: liferay lportal 127.0.0.1(51393) (postgres)
pgsql 70894 0.0 0.8 49724 5908 ?? Is 2:30AM 0:00.67
postgres: liferay lportal 127.0.0.1(65399) (postgres)
pgsql 70895 0.0 0.0 49724 0 ?? IWs - 0:00.00
postgres: liferay lportal 127.0.0.1(54991) (postgres)
pgsql 70896 0.0 0.7 49724 5412 ?? Is 2:30AM 0:00.65
postgres: liferay lportal 127.0.0.1(63123) (postgres)
pgsql 70897 0.0 0.0 49724 0 ?? IWs - 0:00.00
postgres: liferay lportal 127.0.0.1(63978) (postgres)
pgsql 70898 0.0 0.8 49724 6284 ?? Is 2:30AM 0:00.59
postgres: liferay lportal 127.0.0.1(65359) (postgres)
pgsql 70902 0.0 0.6 49724 4264 ?? Is 2:30AM 0:00.25
postgres: liferay lportal 127.0.0.1(50233) (postgres)
pgsql 70903 0.0 0.6 49724 4924 ?? Is 2:30AM 0:00.41
postgres: liferay lportal 127.0.0.1(65401) (postgres)
pgsql 70904 0.0 0.0 49724 0 ?? IWs - 0:00.00
postgres: liferay lportal 127.0.0.1(63124) (postgres)
pgsql 70905 0.0 0.0 49724 0 ?? IWs - 0:00.00
postgres: liferay lportal 127.0.0.1(54153) (postgres)
pgsql 70906 0.0 0.0 49724 0 ?? IWs - 0:00.00
postgres: liferay lportal 127.0.0.1(63712) (postgres)
pgsql 80297 0.0 0.7 49724 5044 ?? Is 6:22AM 0:00.28
postgres: liferay lportal 127.0.0.1(58431) (postgres)
pgsql 80298 0.0 0.7 48700 5288 ?? Is 6:22AM 0:00.48
postgres: liferay lportal 127.0.0.1(50051) (postgres)
pgsql 80299 0.0 1.0 49724 7600 ?? Is 6:22AM 0:00.30
postgres: liferay lportal 127.0.0.1(49678) (postgres)
pgsql 80300 0.0 0.7 48700 5380 ?? Is 6:22AM 0:00.67
postgres: liferay lportal 127.0.0.1(58183) (postgres)
pgsql 80301 0.0 0.6 49724 4748 ?? Is 6:22AM 0:00.37
postgres: liferay lportal 127.0.0.1(55792) (postgres)
pgsql 93527 0.0 0.4 49724 3464 ?? Is 11:28AM 0:00.14
postgres: liferay lportal 127.0.0.1(54222) (postgres)
pgsql 93528 0.0 0.0 48700 0 ?? IWs - 0:00.00
postgres: liferay lportal 127.0.0.1(52385) (postgres)
pgsql 93529 0.0 0.0 48700 0 ?? IWs - 0:00.00
postgres: liferay lportal 127.0.0.1(59677) (postgres)
pgsql 93530 0.0 0.0 48700 0 ?? IWs - 0:00.00
postgres: liferay lportal 127.0.0.1(60016) (postgres)
pgsql 93531 0.0 0.0 49724 0 ?? IWs - 0:00.00
postgres: liferay lportal 127.0.0.1(56885) (postgres)
pgsql 95330 0.0 0.9 49724 6812 ?? Is 12:05PM 0:00.18
postgres: liferay lportal 127.0.0.1(55050) (postgres)
pgsql 95331 0.0 0.7 48700 5680 ?? Is 12:05PM 0:00.07
postgres: liferay lportal 127.0.0.1(53490) (postgres)
pgsql 95332 0.0 0.8 49724 6572 ?? Is 12:05PM 0:00.47
postgres: liferay lportal 127.0.0.1(50029) (postgres)
pgsql 95333 0.0 0.5 48700 3544 ?? Is 12:05PM 0:00.04
postgres: liferay lportal 127.0.0.1(65012) (postgres)
pgsql 95334 0.0 0.8 48700 6236 ?? Is 12:05PM 0:00.06
postgres: liferay lportal 127.0.0.1(57130) (postgres)

It seems I don't have enough memory to run my Liferay web portal,
there are 3 web portal instances are running, but some of the primary
keys are failed to index properly:
..
16:40:18,175 WARN [ResourceActionsUtil:564] Unable to obtain resource
actions for unknown portlet SampleContactUs
17:45:17,326 WARN [PortalImpl:2948] Current URL
/c/portal/login?p_l_id=10404 generates exception: No Layout exists
with the primary key 10404
20:22:57,623 WARN [PortalImpl:2948] Current URL
/c/portal/login?p_l_id=11432 generates exception: No Layout exists
with the primary key 11432
(END)

Your suggestion is very much appreciated.

Thanks