Closed xf_session_activity table overflow due to aggressive site-scraping (AI training?) bots.

Steve Gibson

Active member
Licensed customer
Affected version
We're running v2.2.15
To the brilliant authors of XenForo:

XenForo has a problem when its RAM-based (by default) "xf_session_activity" table overflows catastrophically and brings down its XenForo site.

Many XenForo users and sites are now complaining and drowning under some recent activity that also hit GRC's main forums site. The troublesome queries are coming from an extremely large private, probably residential, proxy network, making IP-based blocking impossible. Thankfully, I found a addon by 'FX' that manages to keep the explosively growing xf_session_activity table from bringing down the site. But this is a weakness XenForo should address.

Our site has been up for many years and we routinely have a great deal of search engine and bot traffic. But what's now happening is at a new level. Our server and bandwidth can handle the load easily... but the XenForo system that we love so much, cannot.
 
Automated triage: Closed

Thank you for reporting this issue. The 'table is full' failure comes from this table using MySQL's MEMORY engine in 2.2, which has a fixed size cap. Since XenForo 2.3.0 the table is converted to InnoDB, which has no such cap, so upgrading should stop this specific failure. If you see problems with this table on 2.3, please open a new report with the details.

This is an automated assessment. A member of staff may review and update it.
 
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