Rene Veerman wrote:
i haven't had the pleasure yet of writing for sites that generate so many hits/sec that they'd update the max value of any table at exactly the same time. i usually ask for the max value about 2 milliseconds before doing the insert. And if the insert fails, i can auto-retry via a wrapper function after sleep(rand(1,3)); I dare say i could work this way at facebook <g> (not that i really want to, happy with where i am)
This is a race condition... all you need are two hits per day... one from person A and one from person B. If they happen within short enough temporal proximity then the race is on.
Now... a big fat lock around the table before the request for max ID and the insert query ought to mitigate your issue. Although I wouldn't call my function getMaxId() I would call it getNextId() :)
Cheers, Rob. -- http://www.interjinn.com Application and Templating Framework for PHP -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
