create table fsm.state_machine (
  shard_id bigint not null,
  id bigint not null generated by default as identity ( start with 1 cache 32767 ),
  statechart_id bigint not null,
  created_at timestamptz not null default now(),

  primary key (shard_id, id),

  constraint fk_statechart
    foreign key(statechart_id)
    references fsm.statechart(id)
    on delete cascade
);

create index idx_statechart on fsm.state_machine(statechart_id);

comment on table fsm.state_machine is
    'Runtime information of a statechart. Contains state machine instances that have started.';