Reduce sessions table

The website I am managing has a session table >1,100,000 records. I want to shrink it and after doing research I have come across 2 options either installing a session expire module which will delete rows from the session table based on the configuration or to make changesin the settings.php file to the following

ini_set('session.cache_expire', 2700);
ini_set('session.cache_limiter', 'none');
ini_set('session.cookie_lifetime', 0);
ini_set('session.gc_maxlifetime', 2700);

I am not sure which of the two options is better, if you could help me that would be great.

Also, I tried using both these options and it reduced the sessions table significantly but it still has > 600,000 records,

Any suggestions will be appreciated.

Thanks