Warning:  [mysql error 1927] Connection was killed

SELECT cat_id AS id, permalink, 1 AS is_old
  FROM old_permalinks
  WHERE permalink IN ('sz-hochhaus', 'sz-hochhaus/tiere')
UNION
SELECT id, permalink, 0 AS is_old
  FROM categories
  WHERE permalink IN ('sz-hochhaus', 'sz-hochhaus/tiere')
; in /data/www/piwigo-13.8.0/include/dblayer/functions_mysqli.inc.php on line 847

Fatal error: Uncaught Error: Call to a member function fetch_assoc() on bool in /data/www/piwigo-13.8.0/include/dblayer/functions_mysqli.inc.php:900 Stack trace: #0 /data/www/piwigo-13.8.0/include/functions_category.inc.php(350): query2array() #1 /data/www/piwigo-13.8.0/include/functions_url.inc.php(511): get_cat_id_from_permalinks() #2 /data/www/piwigo-13.8.0/include/section_init.inc.php(115): parse_section_url() #3 /data/www/piwigo-13.8.0/index.php(12): include('/data/www/piwig...') #4 {main} thrown in /data/www/piwigo-13.8.0/include/dblayer/functions_mysqli.inc.php on line 900


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

REPLACE INTO sessions
  (id,data,expiration)
  VALUES('D849e5dtao4v62us7ugilemm0hgrrj','pwg_lang_switch|s:5:\"sl_SI\";pwg_device|s:7:\"desktop\";pwg_mobile_theme|b:0;pwg_referer_image_id|s:3:\"121\";pwg_image_order|i:10;pwg_index_deriv|s:5:\"small\";',now())
; in /data/www/piwigo-13.8.0/include/dblayer/functions_mysqli.inc.php on line 847