Since the question was about *really* big websites, the answer is both yes and no.
Yes, they do turn off RI on the database side, simply because it's not possible to enforce RI on a database system where data is partitioned across server farms (or shards) both vertically and horizontally. And really big websites can't survive without the data partioning. No, they don't usually turn off RI just to improve performance, because the gains would be minimal, and for big websites, scalability is a much bigger issue that performance (although sometimes one depends on the other), and data partitioning is the way to go to solve the scalability problem. On 5/24/07, Naz Gassiep <[EMAIL PROTECTED]> wrote:
I'm working in a project at the moment that is using MySQL, and people keep making assertions like this one: "*Really* big sites don't ever have referential integrity. Or if the few spots they do (like with financial transactions) it's implemented on the application level (via, say, optimistic locking), never the database level." A large DB working with no RI would give me nightmares. Is it really true that large sites turn RI off to improve performance? Am I just being naive in thinking that everyone runs their DBs with RI in production?
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