Vacuum Problem

Hello all,

I have a problem. The following message keeps appearing in logs :
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WARNING: database "data_base" must be vacuumed within 2606182 transactions
HINT: To avoid a database shutdown, execute a full-database VACUUM in
"data_base".
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Last week I have run : 'vacuumdb -vz -U postgres -ddata_base'
Today it's still listed in 'ps aux'
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postgres 2113 1.0 1.9 26256 20132 ? D Nov26 130:14
postgres: postgres data_base [local] VACUUM
root 2146 0.0 0.1 4616 1508 tty1 Ss Nov28 0:00 -bash
root 2176 0.0 0.0 4648 996 tty1 S+ Nov28 0:00
vacuumdb -vz -U postgres -ddata_base
postgres 2177 0.0 0.3 10260 3572 ? S Nov28 7:12
postgres: postgres data_base [local] VACUUM waiting
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In pg_stat_activity I can see two lines mentionning 'vacuum verbose analyze'

What can I do ??
I really need help

Cedric