Find a row strorage size in database using entity framework

I am about to host my ASP.NET web app solution in the cloud. But I need to find out the following things prior to that:

1. To find the size of a row in the database using entity framework(or lambda expression or even a raw query): My purpose for this task is that a user only gets a fixed size of workspace in the database. To calculate this, I need to sum up the size of the rows for that particular user).

2. To find a size of a DB transaction(eg: Insert, Update, Save, Delete) using entity framework(or lambda expression or raw query): This is to limit the users from adding more data to their workspace if they have exceeded their corresponding storage limits.

3. To find how much of memory it takes for a Business logic to execute.

I am using ASP.NET Core, Entity Framework and Mysql as the database. Can anyone suggest me a way to do this?

Thanks in advance.