diff --git a/pg_monz/userparameter_pgsql.conf b/pg_monz/userparameter_pgsql.conf
index 7166802..bcbdc16 100644
--- a/pg_monz/userparameter_pgsql.conf
+++ b/pg_monz/userparameter_pgsql.conf
@@ -45,7 +45,7 @@ UserParameter=psql.slow_dml_queries[*],psql -h $1 -p $2 -U $3 -d $4 -t -c "selec
 # Database specific examples
 #
 # Get the size of a Database (in bytes)
-UserParameter=psql.db_size[*],psql -h $1 -p $2 -U $3 -d $4 -t -c "select pg_database_size('$5')"
+UserParameter=psql.db_size[*],psql -h $1 -p $2 -U $3 -d $4 -t -c "select pg_database_size('$5') from pg_database where datname = '$5'"
 # Get number of active connections for a specified database
 UserParameter=psql.db_connections[*],psql -h $1 -p $2 -U $3 -d $4 -t -c "select numbackends from pg_stat_database where datname = '$5'"
 # Get number of tuples returned for a specified database