Multi tenant - will it help?

Here is the case , I got users and a few other models , most of them end up doing some action with one main table that contains around 15M rows.

I have an indexed foreign key between the main table and the user model , and plently of specific columns indexes to speed up various queries.

I recently added an Ajax-DataTable view which queries this table for each change , this caused a huge bottleneck in the application.

I think this is happening due to too many calls using the same table.
I'm thinking of migrating the existing application to a multi-tenant strucutre , where each user will have its own main table.
Thus having less locks on the same table.

Anyone have any expirience with anything similar?