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

SELECT data
  FROM piwigo_sessions
  WHERE id = '22E512cmst2b5fkg9vgiri9u6hu6u4'
; 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