DO
$$
DECLARE
  c INT;
  conn_str TEXT DEFAULT
    'host=localhost port=5432 user=tgl dbname=postgres sslmode=disable';
  conn_count INT DEFAULT 50;

  remaining INT;
  finished BOOL[];

  conn TEXT;

  loops INT DEFAULT 10;
  looper INT;

  timer TIMESTAMPTZ;
  inner_timer TIMESTAMPTZ;

  returned TEXT[];

  _found BOOL;
  _idle_wait BOOL DEFAULT false;

  _query TEXT DEFAULT format(
    'DO $d$ DECLARE x INT; BEGIN FOR x IN 1..100 '
    'LOOP RAISE NOTICE ''%s''; END LOOP; END;$d$', lpad('', 1025, 'x'));

BEGIN
  CREATE EXTENSION IF NOT EXISTS dblink;

  PERFORM dblink_connect(
    'test' || s,
    conn_str)
  FROM generate_series(1,conn_count) s;

  timer := clock_timestamp();

  FOR looper in 1..loops
  LOOP
    remaining := conn_count;
    finished = null;

    PERFORM dblink_send_query('test' || s, _query)  FROM generate_series(1,conn_count) s;

    inner_timer := clock_timestamp();

    LOOP
      _found := false;

      FOR c IN 1..conn_count
      LOOP
        IF finished[c]
        THEN
          CONTINUE;
        END IF;

        conn := 'test' || c;

        IF dblink_is_busy('test' || c) = 0
        THEN
          _found := true;

          PERFORM * FROM dblink_get_result(conn) AS R(V TEXT);
          PERFORM * FROM dblink_get_result(conn) AS R(V TEXT);

          finished[c] := true;
          remaining := remaining - 1;

        END IF;
      END LOOP;

      IF NOT _found AND _idle_wait
      THEN
        PERFORM pg_sleep(0.01);
      END IF;

      EXIT WHEN remaining = 0;
    END LOOP;

    RAISE NOTICE 'LOOP: % %', looper, clock_timestamp() - inner_timer;
  END LOOP;

  PERFORM dblink_disconnect('test' || s) FROM generate_series(1,conn_count) s;

END;
$$ LANGUAGE PLPGSQL;