phpmyadmin logs out after 1440 secs
Go to PHPMyAdmin in your browser
Settings > Features > Change the value of Login cookie validity > Save
NOTE: You will have to do this per session.
Add this line to /config.inc.php:
$cfg['LoginCookieValidity'] = 36000;
In /setup/lib/index.lib.php
$cf->getValue('LoginCookieValidity') > 36000;
If you don't already have a .htaccess file for your phpMyAdmin site, create one, and add the following line to override the default PHP session timeout:
php_value session.gc_maxlifetime 36000
I would not recommend altering this value in your main php.ini file, as it will allow a ridiculously long session timeout for all your PHP sites.
source: http://www.sitekickr.com/blog/increase-phpmyadmin-timeout/
We can change the cookie time session feature at:
Settings->Features->General->Login cookie validity
I found the answer in here..No activity within 1440 seconds; please log in again
EDIT:
This solution will work only for the current session, to change permanently do:
open config.inc.php in the root phpMyAdmin directory .
wamp folder: wamp\apps\phpmyadmin{version}\config.inc.php
ubuntu: /etc/phpmyadmin
add this line
$cfg['LoginCookieValidity'] = <your_timeout>;
Example
$cfg['LoginCookieValidity'] = '144000';