Edit your crontab:
[joeuser ~]$ crontab -e
We'll set vacuum up to run nightly at 1 AM. Add the following line:
-0 1 * * * /usr/local/pgsql/bin/vacuumdb $OPENACS_SERVICE_NAME
-
($Id: database-maintenance.xml,v 1.9 -2017/08/07 23:47:54 gustafn Exp $)
+0 1 * * * /usr/local/pgsql/bin/vacuumdb $OPENACS_SERVICE_NAME +