This function changes the database checkpointing interval to the given
      value in minutes. It may also be used to disable checkpointing in two
      ways: By setting checkpoint interval to 0, the checkpoint will only be
      performed after roll forward upon database startup. A setting of -1
      will disable all checkpointing. Main use for this function is to
      ensure a clean online backup of the database slices. Copying of the
      database may take long and checkpointing would modify those files in
      mid-copy, thus rendering the resulting copy unusable. In case the
      system should, for some reason or another, become unstable, it is
      sometimes better to disable checkpointing after a database restart
      to resume backing up from where it was left prior to a system crash.
      Disabling all checkpointing by giving checkpoint_interval the value
      of -1 will do just that.The interval setting will be saved in the server configuration
      file as value of CheckpointInterval in section [Parameters], thus it
      will persist over consecutive server shutdown/restart cycles. A
      long checkpoint_interval setting will produce longer transaction
      logs, which in turn prolongs the time it takes for the database to
      perform a roll forward upon restart in case it was shut down without
      making a checkpoint.