I have seen 2 of these errors occur in 1.13.2, over the past few weeks.
DanB
..."SiteStatsUpdate::doUpdate". MySQL returned error "1213: Deadlock found when trying to get lock; try restarting transaction
Which MediaWiki version? This was supposed to be fixed on 1.13.1 (update to 1.13.2). Although to never get those deadlocks, you should use memcached.