create table task_definitions (
  task_definition_name text not null,
  dependencies ,
  executable ,
  max_attempts integer not null,
  max_runtime_seconds integer,
  backoff_base_seconds integer not null,
  backoff_exponent numeric not null default 1,
  require_explicit_success boolean not null default false
);
comment on table task_definitions is '
  An individual task that runs as part of a process
';

comment on column task_definitions.task_definition_name is '
  The canonical name for this task used by other tasks to identify this task
';
comment on column task_definitions.dependencies is '
  The tasks that must have completed prior to this one beginning
';
comment on column task_definitions.max_runtime_seconds is '
  The execution time (for a single attempt) after which the system will kill the task
';
comment on column task_definitions.require_explicit_success is '
  If true, the task must explicitly update its status with Sundial in order to succeed.
';