Just got this: Mysqli statement execute error, I have seen these in the logs before but never been able to work out what it was. This time I couldn't access the forum as the error stopped anything else loading.
How do i track down what this is ? Everything has been running fine till now !
Unfortunately no. It appears to be a MySQL bug as it seems to happen in very specific circumstances and is sometimes triggered by high load. Updating MySQL has generally fixed it.
If your XenForo seems fairly slow, it could be the load issue so if you can get switched to a different server in their batch, that may help. (Obviously if your host is slow to respond to tickets, you wouldn't be wrong in looking for a new host...)