If you get the error message " *Warning*: MySQL server has gone away", that means your Php or Perl/cgi powered application has not passed a query for a while. The connection to MySQL times out. To start up a new and simple query session, select a table within the database of that application via PhpMyAdmin.
If that does not help, you need to tweak MySQL conf file. Using your favorite Linux text editor such as: vi or pico, open MySQL conf file "/etc/my.cnf".
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vi /etc/my.cnf
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Set the following values for these two variables:
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connect_timeout=120
wait_timeout=1800
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If these values do not help, you can increase them.
Then restart MySQL. This command will restart MySQL daemon on most generic Linux servers:
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/sbin/service mysqld restart
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If you do not have a my.cnf file, create a new one. The local path on most generic Linux servers is: /etc/my.cnf
To view MySQL variables and their current values, run the following command at the prompt:
/usr/bin/mysql -uroot -pYOUR_ROOT_PASSWD
Then, run the following command (one single line) at MySQL prompt:
mysql> show global variables like '%timeout%';
Which will show a result like this:
+-------------------------------+-------+
| Variable_name | Value |
+-------------------------------+-------+
| connect_timeout | 5 |
| delayed_insert_timeout | 300 |
| innodb_lock_wait_timeout | 50 |
| interactive_timeout | 28800 |
| net_read_timeout | 30 |
| net_write_timeout | 60 |
| slave_net_timeout | 3600 |
| table_lock_wait_timeout | 50 |
| wait_timeout | 28800 |
+-------------------------------+-------+
9 rows in set (0.00 sec)
As mentioned earlier, you can change the values of the connect_timeout and net_write_timeout. The higher the values are, the longer MySQL stays active and can process longer queries.
