Warning: [mysql error 144] Table './photo/piwigo_sessions' is marked as crashed and last (automatic?) repair failed

SELECT data
  FROM piwigo_sessions
  WHERE id = '36E2qr00c3cegcnr0lmf19c8avh8u1'
; in /var/www/harmsen.net/html/photo/include/dblayer/functions_mysqli.inc.php on line 845
Fatal error: Call to a member function fetch_assoc() on a non-object in /var/www/harmsen.net/html/photo/include/dblayer/functions_mysqli.inc.php on line 226