>>> "*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."
Sure, but in the forum benchmark I just did, when using MyISAM, with no
reference integrity checks, at the end of the benchmark, there is an
impressive number of records with broken foreign key relations... when the
user kills his HTTP connection or reloads at the wrong moment, and the
script is interrupted, or killed by an exception or whatever, boom.