How to handle Large no of inputs

I have a form with dynamic number of inputs and it could reach up to 100k input fields. When I submit the form it is taking way to long to process and insert into database. Is there any way to make this process faster. I am using PHP (Codeignite 3) as programming language and mysql as database. Also when the form is in process of submitting all other pages will not load either. 
Its a software with inventory and POS and and when they buy the product I have to keep track of the product by serial no which is unique for each product. When they buy product sometimes its in tens of thousands in quantities so it requires all the fields.
It has a serial number auto generator which takes starting serial number and quantity and generates that number of serial numbers. eg. if I have 10 products coming with 3 having sn01-sn03, mn01-mn04 and ss01-ss-03. I would provide relative data like starting number sn01 and quantity 3 and it will generate that . and you don't need to scan/enter every item since the package cartoon box comes with the starting no and no of item in it. and since they might have some mismatch as well so I need all the input for that.
I need to send all the serial numbers which can amount to thousands of input fields. and when submitting the form it takes to long to insert in database and if I have any other active pages and wants to navigate to other pages, it will not, it waits for the process to be complete. I am using xampp. input fields can amount to 100k input fields
Stackoverflow link: php - How to handle Large no of inputs - Stack Overflow

Thanks for the help in advance...