anchor.diff:  
   # These settings are ignored on a standby server
   
  -#max_wal_senders = <%= node["postgresql"]["max_wal_senders"] %>    # max number of walsender processes
  +<%- if node["postgresql"]["max_wal_senders"] %>
  +max_wal_senders = <%= node["postgresql"]["max_wal_senders"] %>    # max number of walsender processes
  +<%- end %>
           # (change requires restart)
   #wal_sender_delay = <%= node["postgresql"]["wal_sender_delay"] %>    # walsender cycle time, 1-10000 milliseconds
  -#wal_keep_segments = <%= node["postgresql"]["wal_keep_segments"] %>    # in logfile segments, 16MB each; 0 disables
  +<%- if node["postgresql"]["wal_keep_segments"] %>
  +wal_keep_segments = <%= node["postgresql"]["wal_keep_segments"] %>    # in logfile segments, 16MB each; 0 disables
  +<%- end %>
   #vacuum_defer_cleanup_age = <%= node["postgresql"]["vacuum_defer_cleanup_age"] %> # number of xacts by which cleanup is delayed
   #replication_timeout = <%= node["postgresql"]["replication_timeout"] %>  # in milliseconds; 0 disables
   #synchronous_standby_names = '<%= node["postgresql"]["synchronous_standby_names"] %>' # standby servers that provide sync rep
  
positive.code:           # requires logging_collector to be on.
  
  # This is used when logging to stderr:
  #logging_collector = <%= node["postgresql"]["logging_collector"] %>    # Enable capturing of stderr and csvlog
            # into log files. Required to be on for
            # csvlogs.
            # (change requires restart)
  
negative.code: 
  # - Checkpoints -
  
  <%- if node["postgresql"]["checkpoint_segments"] %>
  checkpoint_segments = <%= node["postgresql"]["checkpoint_segments"] %>    # in logfile segments, min 1, 16MB each
  <%- end %>
  #checkpoint_timeout = <%= node["postgresql"]["checkpoint_timeout"] %>    # range 30s-1h
  #checkpoint_completion_target = <%= node["postgresql"]["checkpoint_completion_target"] %> # checkpoint target duration, 0.0 - 1.0
  #checkpoint_warning = <%= node["postgresql"]["checkpoint_warning"] %>   # 0 disables
  
  # - Archiving -
  
  
  <%- if node["postgresql"]["archive_mode"] %>
  archive_mode = <%= node["postgresql"]["archive_mode"] %>   # allows archiving to be done
  <%- end %>
  
          # (change requires restart)
  <%- if node["postgresql"]["archive_command"] %>
  archive_command = '<%= node["postgresql"]["archive_command"] %>'   # command to use to archive a logfile segment
  <%- end %>
  #archive_timeout = <%= node["postgresql"]["archive_timeout"] %>    # force a logfile segment switch after this
          # number of seconds; 0 disables
  
  