Question

I tried to import a large sql file through phpMyAdmin…But it kept showing error

‘MySql server has gone away’

What to do?

Answer 1

As stated here:

Two most common reasons (and fixes) for the MySQL server has gone away
(error 2006) are:

Server timed out and closed the connection. How to fix:

1. check that wait_timeout variable in your mysqld’s my.cnf configuration file is large enough. On Debian: sudo nano
/etc/mysql/my.cnf, set wait_timeout = 600 seconds (you can
   tweak/decrease this value when error 2006 is gone), then sudo
/etc/init.d/mysql restart. I didn’t check, but the default value for
   wait_timeout might be around 28800 seconds (8 hours).

2. Server dropped an incorrect or too large packet. If mysqld gets a packet that is too large or incorrect, it assumes that something has
   gone wrong with the client and closes the connection. You can increase
   the maximal packet size limit by increasing the value of
   max_allowed_packet in my.cnf file. On Debian: sudo nano
/etc/mysql/my.cnf, set max_allowed_packet = 64M (you can
   tweak/decrease this value when error 2006 is gone), then sudo
/etc/init.d/mysql restart.

Edit:

Notice that MySQL option files do not have their commands already available as comments (like in php.ini for instance). So you must type any change/tweak in my.cnf or my.ini and place them in mysql/data directory or in any of the other paths, under the proper group of options such as [client], [myslqd], etc. For example:

[mysqld]
wait_timeout = 600
max_allowed_packet = 64M

Then restart the server. To get their values, type in the mysql client:

> select @@wait_timeout;
> select @@max_allowed_packet;