func TestPoolReleaseDiscardsDeadConnections(t *testing.T) {
	t.Parallel()

	maxConnections := 3
	pool := createConnPool(t, maxConnections)
	defer pool.Close()

	var c1, c2 *pgx.Conn
	var err error
	var stat pgx.ConnPoolStat

	if c1, err = pool.Acquire(); err != nil {
		t.Fatalf("Unexpected error acquiring connection: %v", err)
	}
	defer func() {
		if c1 != nil {
			pool.Release(c1)
		}
	}()

	if c2, err = pool.Acquire(); err != nil {
		t.Fatalf("Unexpected error acquiring connection: %v", err)
	}
	defer func() {
		if c2 != nil {
			pool.Release(c2)
		}
	}()

	if _, err = c2.Exec("select pg_terminate_backend($1)", c1.Pid); err != nil {
		t.Fatalf("Unable to kill backend PostgreSQL process: %v", err)
	}

	// do something with the connection so it knows it's dead
	rows, _ := c1.Query("select 1")
	rows.Close()
	if rows.Err() == nil {
		t.Fatal("Expected error but none occurred")
	}

	if c1.IsAlive() {
		t.Fatal("Expected connection to be dead but it wasn't")
	}

	stat = pool.Stat()
	if stat.CurrentConnections != 2 {
		t.Fatalf("Unexpected CurrentConnections: %v", stat.CurrentConnections)
	}
	if stat.AvailableConnections != 0 {
		t.Fatalf("Unexpected AvailableConnections: %v", stat.CurrentConnections)
	}

	pool.Release(c1)
	c1 = nil // so it doesn't get released again by the defer

	stat = pool.Stat()
	if stat.CurrentConnections != 1 {
		t.Fatalf("Unexpected CurrentConnections: %v", stat.CurrentConnections)
	}
	if stat.AvailableConnections != 0 {
		t.Fatalf("Unexpected AvailableConnections: %v", stat.CurrentConnections)
	}
}