$cat ~/.logstash_jdbc_last_run
--- 2017-03-08 09:29:00.259000000 Z

$date
mer  8 mar 2017, 10.29.31, CET
$cat /etc/timezone
Europe/Rome

input {
  jdbc {
    # Postgres jdbc connection string to our database, mydb
    jdbc_connection_string => "jdbc:postgresql://localhost:5432/postgres"
    # The user we wish to execute our statement as
    jdbc_user => "logstash"
    jdbc_password => "logstashpass"
    # The path to our downloaded jdbc driver
    jdbc_driver_library => "/home/trex/Development/ship_to_elasticsearch/software/postgresql-42.0.0.jar"
    # The name of the driver class for Postgresql
    jdbc_driver_class => "org.postgresql.Driver"
    jdbc_default_timezone => "Europe/Rome"
    # our query
    statement => "SELECT * FROM contacts WHERE timestamp > :sql_last_value"
    # every 1 min
    schedule => "*/1 * * * *"
  }
}
output {
  stdout { codec => json_lines }
  elasticsearch {
    hosts => [ "localhost:9200" ]
    index => "database.%{+yyyy.MM.dd.HH}"
  }
}

postgres=# select * from "contacts";                                                                                               uid |         timestamp          |          email          | first_name | last_name
-----+----------------------------+-------------------------+------------+------------
   1 | 2017-03-07 18:09:25.358684 | jim@example.com         | Jim        | Smith
   2 | 2017-03-07 18:09:25.3756   |                         | John       | Smith
   3 | 2017-03-07 18:09:25.384053 | carol@example.com       | Carol      | Smith
   4 | 2017-03-07 18:09:25.869833 | sam@example.com         | Sam        |
   5 | 2017-03-08 10:04:26.39423  | trex@example.com        | T          | Rex