Postgresql agent script produces no output

 $ lsb_release -a No LSB modules are available. Distributor ID: Debian Description: Debian GNU/Linux 9.4 (stretch) Release: 9.4 Codename: stretch $ perl --version This is perl 5, version 24, subversion 1 (v5.24.1) built for x86_64-linux-gnu-thread-multi (with 80 registered patches, see perl -V for more detail) $ dpkg -l | grep -Ei "(postgresql|libdbi|libdbd)" ii libdbd-pg-perl 3.7.4-1~pgdg90+1 amd64 Perl DBI driver for the PostgreSQL database server ii libdbi-perl 1.636-1+b1 amd64 Perl Database Interface (DBI) ii libpq5:amd64 10.4-1.pgdg80+1 amd64 PostgreSQL C client library ii pgbadger 9.2-1.pgdg80+1 all Fast PostgreSQL log analysis report ii pgdg-keyring 2017.3 all keyring for apt.postgresql.org ii postgresql-10 10.4-1.pgdg80+1 amd64 object-relational SQL database, version 10 server ii postgresql-9.5 9.5.13-1.pgdg80+1 amd64 object-relational SQL database, version 9.5 server ii postgresql-9.6 9.6.9-1.pgdg80+1 amd64 object-relational SQL database, version 9.6 server ii postgresql-client-10 10.4-1.pgdg80+1 amd64 front-end programs for PostgreSQL 10 ii postgresql-client-9.5 9.5.13-1.pgdg80+1 amd64 front-end programs for PostgreSQL 9.5 ii postgresql-client-9.6 9.6.9-1.pgdg80+1 amd64 front-end programs for PostgreSQL 9.6 ii postgresql-client-common 191.pgdg80+1 all manager for multiple PostgreSQL client versions ii postgresql-common 191.pgdg80+1 all PostgreSQL database-cluster manager ii postgresql-contrib 10+191.pgdg80+1 all additional facilities for PostgreSQL (supported version) ii postgresql-contrib-9.5 9.5.13-1.pgdg80+1 amd64 additional facilities for PostgreSQL ii postgresql-contrib-9.6 9.6.9-1.pgdg80+1 amd64 additional facilities for PostgreSQL $ pg_lsclusters Ver Cluster Port Status Owner Data directory Log file 9.5 main 5432 online postgres /var/lib/postgresql/9.5/main /var/log/postgresql/postgresql-9.5-main.log 9.6 main 5433 online postgres /var/lib/postgresql/9.6/main /var/log/postgresql/postgresql-9.6-main.log 10 main 5434 online postgres /var/lib/postgresql/10/main /var/log/postgresql/postgresql-10-main.log