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XF 1.5 What Is Causing Deadlocks


Well-known member
Need some help from the xF team here. Basically our site has been having ongoing issues with mySQL being locked up which as a result we have to constantly reset mySQL every 30 minutes. Keeping it short and simple:

1). There are no errors explaining why this is happening
2). We have optimized the site twice already
3). We have implemented caching all around
4). We have done a variety of other things

Here is what we're planning to do

1). Upgrade to 1.5.9
2). If the upgrade doesn't we will use 3rd party assistance reviewing our databases

In case the 1.5.9 upgrade doesn't solve the issue, I'm looking for some recommendations on what we should do to try to find what is causing this. I assume one of them will be disable add ons 1 by 1. What other recommendations do you have?

Digital Doctor

Well-known member
This comes up alot so there is a Tip sheet on it.
Of course, as Forum Searching is ineffective, people never find it.

P: I have seen a "Deadlock found when trying to get a lock" MySQL error in my error logs.
S: Reload the page to restart whatever process you were attempting. Deadlocks can occur with any transaction or query in an InnoDB MySQL database. They are very difficult to programmatically prevent and shouldn't occur often. If they occur fairly often, it is recommended that you discuss possible solutions with your host. Here is some further reading related to deadlocks: