->/opt/lampp/etc/php.ini
1)increase them accordingly 
 post_max_size=500M
upload_max_filesize=500M
max_input_time = 600
memory_limit=900M
max_execution_time=-1

->in opt/lampp/etc/my.cnf
max_allowed_packet=1000
innodb_log_file_size = 50M

->phpMyAdmin\libraries\config.default.php
$cfg['ExecTimeLimit'] = 0;
______________________________________________
2nd method 

goto lampp/phpmyadmin
create two folders in the same directory namely save and upload 

goto lampp/phpmyadmin/config.inc.php
$cfg['UploadDir'] = '/opt/lampp/phpmyadmin/upload';
$cfg['SaveDir'] = '/opt/lampp/phpmyadmin/save';

save 
and then put the large .SQL file into the upload folder 
it will come under the import page automatically