Warning:  [mysql error 2006] MySQL server has gone away

SELECT id
  FROM piwigo_images i 
    INNER JOIN piwigo_image_category ic ON id=ic.image_id
    INNER JOIN piwigo_image_tag it ON id=it.image_id
    WHERE tag_id IN (116,325,712,4223)
  AND (category_id NOT IN (2052,2053,2056,2111,1821,1824,2123,1818,1819,2017,1869,1882,1884,1887,1899,1902,1904,1905,1906,1908,1915,1918,1919,1921,1922,1924,1930,1931,1935,1936,1939,1940,1944))
  GROUP BY id
  HAVING COUNT(DISTINCT tag_id)=4
ORDER BY date_creation DESC, date_available DESC in /home/users4/s/sbouilland/www/Photos/include/dblayer/functions_mysqli.inc.php on line 847

Fatal error: Uncaught Error: Call to a member function fetch_assoc() on bool in /home/users4/s/sbouilland/www/Photos/include/dblayer/functions_mysqli.inc.php:908 Stack trace: #0 /home/users4/s/sbouilland/www/Photos/include/functions_tag.inc.php(231): query2array('\nSELECT id\n FR...', NULL, 'id') #1 /home/users4/s/sbouilland/www/Photos/include/section_init.inc.php(338): get_image_ids_for_tags(Array) #2 /home/users4/s/sbouilland/www/Photos/index.php(12): include('/home/users4/s/...') #3 {main} thrown in /home/users4/s/sbouilland/www/Photos/include/dblayer/functions_mysqli.inc.php on line 908


Warning:  [mysql error 2006] MySQL server has gone away

REPLACE INTO piwigo_sessions
  (id,data,expiration)
  VALUES('1275aad6833f9e86644ae7b016de75289aee','pwg_device|s:7:\"desktop\";',now())
; in /home/users4/s/sbouilland/www/Photos/include/dblayer/functions_mysqli.inc.php on line 847