Auto number for big data I'm working with application that can have millions of data. Just wondering if it is ok to use auto_number as primary key. I have read that bigint, int etc has limit. So for example site is on live for 10 years. Is it ok to use auto_number in it. Does big websites like facebook also use auto_number as their primary key?
Assuming you're using a 64 bit system, an INT(eger), 2^64  =   18,446,744,073,709,551,616, so if you have an insert every nanosecond, your system will run out of numbers after approximately 600 years - I wouldn't worry too much! :-)