While working with large databases, phpMyAdmin is in serveral cases not the perfect application to handle changes and or administrate the databases but may the only one you are allowed to use.

In this order there are two default configuration the following to configuration vars will help you to work better and faster.

Show all rows without a limit:

$cfg['ShowAll'] = true;

Show full update statements:

$cfg['MaxCharactersInDisplayedSQL'] = 2147483647;

In order to the default value, updates with more than 1000 chars will be replaced with […].

Just place these in the config.inc.php e.g. /var/www/htdocs/phpmyadmin/config.inc.php