I am getting 'Lost connection to MySQL server' and '2006: MySQL server has gone away' errors so frequently that the server is unusable. There are questions related to this issue in SO, but none that apply to my situation; for instance, there is no network connection (the server is connected by a socket to the client process which is on the same machine) and there are no long queries (the machine is running a number of CMS - mediawiki, drupal and joomla - and PHPMyAdmin, but there is nothing exceptional about the queries generated, AFAIK).
I have increased all the timeouts to the point where they must surely be sufficient:
+-----------------------------+----------+
| Variable_name | Value |
+-----------------------------+----------+
| connect_timeout | 60 |
| delayed_insert_timeout | 300 |
| innodb_flush_log_at_timeout | 1 |
| innodb_lock_wait_timeout | 50 |
| innodb_rollback_on_timeout | OFF |
| interactive_timeout | 28800 |
| lock_wait_timeout | 31536000 |
| net_read_timeout | 6000 |
| net_write_timeout | 6000 |
| rpl_stop_slave_timeout | 31536000 |
| slave_net_timeout | 3600 |
| wait_timeout | 28800 |
| max_allowed_packet | 16777216 |
+-----------------------------+----------+
I have also changed the connect_timeout setting in php.ini to unlimited:
; Maximum time (in seconds) for connect timeout. -1 means no limit
; http://php.net/mysql.connect-timeout
mysql.connect_timeout = -1
Restarting the server clears the problem for some hours. After that, every access through the CMSs (i.e. through PHP) and through a small PHP test program with a trivial query fails. However, I can still access the MySQL server and the databases through the MySQL client.
There are no error messages in the MySQL error log.
The server is running on a recent Mac Mini, using Mac OS X 10.9.5, MySQL v5.6.22 and PHP v5.6.3 installed using Mac Port.
Can you help with ideas where I should look to deal with this?