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

SELECT data
  FROM piwigo_sessions
  WHERE id = '22E7gkd5bnu7umpnqlf52hno10kas0'
; in /home/sarah/public_html/piwigo/include/dblayer/functions_mysqli.inc.php on line 845

Call Stack:
    0.0001     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
    0.1173     605552   3. session_start() /home/sarah/public_html/piwigo/include/common.inc.php:156
    0.1173     606312   4. pwg_session_read() /home/sarah/public_html/piwigo/include/common.inc.php:156
    0.1173     606504   5. pwg_query() /home/sarah/public_html/piwigo/include/functions_session.inc.php:147
    0.1182     606728   6. my_error() /home/sarah/public_html/piwigo/include/dblayer/functions_mysqli.inc.php:147
    0.1182     607072   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: 0.0001 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 0.1173 605552 3. session_start() /home/sarah/public_html/piwigo/include/common.inc.php:156 0.1173 606312 4. pwg_session_read() /home/sarah/public_html/piwigo/include/common.inc.php:156 0.1184 606680 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('22E7gkd5bnu7umpnqlf52hno10kas0','',now())
; in /home/sarah/public_html/piwigo/include/dblayer/functions_mysqli.inc.php on line 845

Call Stack:
    0.0001     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
    0.1173     605552   3. session_start() /home/sarah/public_html/piwigo/include/common.inc.php:156
    0.1173     606312   4. pwg_session_read() /home/sarah/public_html/piwigo/include/common.inc.php:156
    0.1184     606680   5. pwg_db_fetch_assoc() /home/sarah/public_html/piwigo/include/functions_session.inc.php:148
    0.1184     606824   6. session_write_close() /home/sarah/public_html/piwigo/include/functions_session.inc.php:0
    0.1184     607128   7. pwg_session_write() /home/sarah/public_html/piwigo/include/functions_session.inc.php:0
    0.1184     607336   8. pwg_query() /home/sarah/public_html/piwigo/include/functions_session.inc.php:169
    0.1186     607432   9. my_error() /home/sarah/public_html/piwigo/include/dblayer/functions_mysqli.inc.php:147
    0.1187     607800  10. trigger_error() /home/sarah/public_html/piwigo/include/dblayer/functions_mysqli.inc.php:845