DB Error: Table './mercator/sessions' is marked as crashed and should be repaired

Stack Trace:

File: /srv/www-ojs/cc/mercator/lib/pkp/classes/session/SessionDAO.inc.php line 44
Function: DAO->retrieve("SELECT * FROM sessions WHERE session_id = ?", Array(1))

File: /srv/www-ojs/cc/mercator/lib/pkp/classes/session/SessionManager.inc.php line 169
Function: SessionDAO->getSession("ibr6ektid52tmbhqpqd9u65164")

File: (unknown) line (unknown)
Function: SessionManager->read("ibr6ektid52tmbhqpqd9u65164")

File: /srv/www-ojs/cc/mercator/lib/pkp/classes/session/SessionManager.inc.php line 59
Function: session_start()

File: /srv/www-ojs/cc/mercator/lib/pkp/classes/session/SessionManager.inc.php line 130
Function: SessionManager->__construct(Object(SessionDAO), Object(Request))

File: /srv/www-ojs/cc/mercator/lib/pkp/classes/security/Validation.inc.php line 367
Function: SessionManager::getManager()

File: /srv/www-ojs/cc/mercator/lib/pkp/classes/core/PKPPageRouter.inc.php line 73
Function: Validation::isLoggedIn()

File: /srv/www-ojs/cc/mercator/lib/pkp/classes/core/Dispatcher.inc.php line 117
Function: PKPPageRouter->isCacheable(Object(Request))

File: /srv/www-ojs/cc/mercator/lib/pkp/classes/core/PKPApplication.inc.php line 227
Function: Dispatcher->dispatch(Object(Request))

File: /srv/www-ojs/cc/mercator/index.php line 68
Function: PKPApplication->execute()