Функции wait_for_replication_replay и wait_till_master_shutsdown реализовать через for

[andr-sokolov]

$$
declare
  b bool;
begin
  for i in 0..retries loop
    select flush_location=pg_current_xlog_location() into b
      from pg_stat_replication;
    if b then
      return true;
    end if;

    perform pg_sleep(0.1);
    perform pg_stat_clear_snapshot();
  end loop;

  return false;
end;
$$ language plpgsql;```