After a few minutes, the connection to the MySQL server is lost. This happens on large querys (since a few weeks) and since two(?) days on small query's as well.
Example (large query):
MariaDB [commonswiki_p]> SELECT CURRENT_TIME();
+----------------+
| CURRENT_TIME() |
+----------------+
| 07:34:14 |
+----------------+
1 row in set (0.00 sec)
MariaDB [commonswiki_p]> SET SESSION optimizer_switch='materialization=off';
Query OK, 0 rows affected (0.06 sec)
MariaDB [commonswiki_p]> SELECT concat('File:', p.page_title) AS fqp
-> FROM page p
-> LEFT JOIN templatelinks
-> ON tl_title IN ('Uncategorized', 'Uncategorized-Geograph', 'Check_categories', 'Uncategorized-PIB', 'Uncategorized-Polona')
-> AND tl_namespace = 10
-> AND page_id = tl_from
-> LEFT JOIN categorylinks
-> ON page_id = cl_from
-> AND (
-> SELECT page_id AS id
-> FROM page ppp
-> WHERE ppp.page_namespace = 14
-> AND ppp.page_title = cl_to
-> ) NOT IN (
-> SELECT DISTINCT pp_page
-> FROM page_props
-> WHERE pp_propname IN ('hiddencat')
-> )
-> WHERE p.page_namespace = 6
-> AND cl_from IS NULL
-> AND tl_from IS NULL
-> AND page_is_redirect = 0
-> -- group by p.page_id
-> -- order by p.page_latest asc
-> LIMIT 100;
ERROR 2013 (HY000): Lost connection to MySQL server during query
MariaDB [commonswiki_p]> SELECT CURRENT_TIME();
ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect...
Connection id: 35319303
Current database: commonswiki_p
+----------------+
| CURRENT_TIME() |
+----------------+
| 07:39:26 |
+----------------+
1 row in set (4.00 sec)Example (smaller query):
MariaDB [commonswiki_p]> SELECT CURRENT_TIME();
+----------------+
| CURRENT_TIME() |
+----------------+
| 07:57:40 |
+----------------+
1 row in set (0.00 sec)
MariaDB [commonswiki_p]> SELECT
-> actor_name AS user,
-> COUNT(log_timestamp) AS ucount
-> FROM logging_userindex
-> INNER JOIN actor_logging
-> ON log_actor = actor_id
-> WHERE log_type = 'delete'
-> AND log_action = 'delete'
-> GROUP BY actor_name
-> ORDER by ucount DESC;
ERROR 2013 (HY000): Lost connection to MySQL server during query
MariaDB [commonswiki_p]> SELECT CURRENT_TIME();
ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect...
Connection id: 35396331
Current database: commonswiki_p
+----------------+
| CURRENT_TIME() |
+----------------+
| 08:02:55 |
+----------------+
1 row in set (5.20 sec)