General question on reasonable amount of custom fields and database productivity

[isuv]

Dear all,

I'm working on a website based on Joomla 2.5.8+VM2.0.16. My question is general and refers to speed and productivity of mysql database for the project. I see, that all the data in custom fields and related products are stored in one table prefix_virtuemart_product_customfields. My client wants more than 20 customfields + information about related products. There are thousands of products. I would like to get some advice from a professional, if that reasonable to make so many customfields. How many products approximately will be served by the database without loosing in speed and quality. If i take 30 rows for each product in the table prefix_virtuemart_product_customfields, i get 900 000 rows for 30 000 products. Will this slow down server very much? There will be also rather many visitors of the website (hundreds and even thousands). So my question is how many products will be possible to store in the database without loosing in speed and quality of database work. Will the situation be better if we keep information in the fields "product description" instead of some customfields or this will be the same?