what is customdb? and how it's work ?

The CustomDB plugin is meant to let you store data from the user's social network profile into any database table you want. You can even store the data in a completely separate database if you choose.

It's definitely a more advanced configuration option that not many users will use, but it does allow a lot of flexibility to import profile data into extensions or other tables we don't support by default.

To use, simply add the database information, if you want to use a separate database from your Joomla one. Then, hit save and configure the main column that will be the primary key for either the user's Joomla ID or their Social Network Id and then select how the data is imported from the social network into the selected table.

I hope that helps explain. Of course, if you need more assistance or have other questions, just let me know.

Thanks,
Alex