This is a very good question. It depends on many things, the number of tables, rows, what is in them, etc.
edit: ok, you did the editing. "For this question, imagine about 20 tables with 9 fields each. Not empty for each field." 1 database, 20 tables, 9 fields each, we say varchar (16).
I would say about 300,000 (300K) rows, but it depends on the type of database structure (innoDB or other types)
source
share