Warning: [mysql error 145] Table './sarah/piwigo_sessions' is marked as crashed and should be repaired

SELECT data
  FROM piwigo_sessions
  WHERE id = '23ABpl9kspi0e7giuvqd71g6k50p65'
; in /home/sarah/public_html/piwigo/include/dblayer/functions_mysqli.inc.php on line 845

Call Stack:
    0.0000     241600   1. {main}() /home/sarah/public_html/piwigo/picture.php:0
    0.0001     242536   2. include_once('/home/sarah/public_html/piwigo/include/common.inc.php') /home/sarah/public_html/piwigo/picture.php:25
    0.0020     605392   3. session_start() /home/sarah/public_html/piwigo/include/common.inc.php:156
    0.0020     606152   4. pwg_session_read() /home/sarah/public_html/piwigo/include/common.inc.php:156
    0.0020     606344   5. pwg_query() /home/sarah/public_html/piwigo/include/functions_session.inc.php:147
    0.0026     606568   6. my_error() /home/sarah/public_html/piwigo/include/dblayer/functions_mysqli.inc.php:147
    0.0026     606912   7. trigger_error() /home/sarah/public_html/piwigo/include/dblayer/functions_mysqli.inc.php:845

Fatal error: Call to a member function fetch_assoc() on boolean in /home/sarah/public_html/piwigo/include/dblayer/functions_mysqli.inc.php on line 226 Call Stack: 0.0000 241600 1. {main}() /home/sarah/public_html/piwigo/picture.php:0 0.0001 242536 2. include_once('/home/sarah/public_html/piwigo/include/common.inc.php') /home/sarah/public_html/piwigo/picture.php:25 0.0020 605392 3. session_start() /home/sarah/public_html/piwigo/include/common.inc.php:156 0.0020 606152 4. pwg_session_read() /home/sarah/public_html/piwigo/include/common.inc.php:156 0.0028 606520 5. pwg_db_fetch_assoc() /home/sarah/public_html/piwigo/include/functions_session.inc.php:148
Warning: [mysql error 145] Table './sarah/piwigo_sessions' is marked as crashed and should be repaired

REPLACE INTO piwigo_sessions
  (id,data,expiration)
  VALUES('23ABpl9kspi0e7giuvqd71g6k50p65','',now())
; in /home/sarah/public_html/piwigo/include/dblayer/functions_mysqli.inc.php on line 845

Call Stack:
    0.0000     241600   1. {main}() /home/sarah/public_html/piwigo/picture.php:0
    0.0001     242536   2. include_once('/home/sarah/public_html/piwigo/include/common.inc.php') /home/sarah/public_html/piwigo/picture.php:25
    0.0020     605392   3. session_start() /home/sarah/public_html/piwigo/include/common.inc.php:156
    0.0020     606152   4. pwg_session_read() /home/sarah/public_html/piwigo/include/common.inc.php:156
    0.0028     606520   5. pwg_db_fetch_assoc() /home/sarah/public_html/piwigo/include/functions_session.inc.php:148
    0.0028     606664   6. session_write_close() /home/sarah/public_html/piwigo/include/functions_session.inc.php:0
    0.0028     606968   7. pwg_session_write() /home/sarah/public_html/piwigo/include/functions_session.inc.php:0
    0.0028     607176   8. pwg_query() /home/sarah/public_html/piwigo/include/functions_session.inc.php:169
    0.0030     607272   9. my_error() /home/sarah/public_html/piwigo/include/dblayer/functions_mysqli.inc.php:147
    0.0030     607640  10. trigger_error() /home/sarah/public_html/piwigo/include/dblayer/functions_mysqli.inc.php:845