Inserting large dataset from CSV file with CI Model

One of these links should help you get the job done.

MySQLi - 13.2.7 LOAD DATA Statement

Insert a large data from csv file into database

How to Batch Import Huge CSV Fast using PHP (Million Records in Seconds)

Thank you, All of them are helpful indeed, but I want to process it through my model, for validations, beforeInsert callbacks etc. 

When I set model variable to null, garbage collector should work. So free the memory. If after every insert can free the overhead, then it's only about timeout. But something does not free the memory I think.