RES: Degradation of postgres 7.4.5 on FreeBSD/CygWin

Hi,

this is only max 15 concurrent conections. And is not a heavy performance
database, so i think this is not necessary vacumm more than once a day.

In another customer, has only 5 users and the database have 300mb, small
database, and has the same behaviour (haven't modified postgresql).
My first instalation was not changed anything in postgresql.conf, but in
this new server (FreeBSD) i have changed some parameters.

as showed in my crontab list, i think this is enough:
00 13 * * 1-5 /bin/sh /home/postgres/backup.sh >/dev/null 2>&1
00 19 * * 1-5 /bin/sh /home/postgres/backup.sh >/dev/null 2>&1
00 23 * * 1-5 /usr/local/pgsql/bin/psql supre -c "vacuum analyze;"
>>/dev/null 2>&1
00 23 * * 6 /usr/local/pgsql/bin/psql supre -c "reindex database supre;"
>>/dev/null 2>&1
00 23 * * 7 /usr/local/pgsql/bin/psql supre -c "vacuum full analyze;"
>>/dev/null 2>&1

These my changed configs in postgresql.conf:
max_connections = 30
shared_buffers = 8192
sort_mem = 32768
vacuum_mem = 32768
max_fsm_pages = 40000
max_fsm_relations = 2000

But why after 2 months the database has 1.3gb and after reimport on 900mb ?

Both customer are smaller databases, but one of them, has 8 years os data,
it's the reason of size 900mb, these are too smaller database.

Regards
Rodrigo Moreno