When changing the icon of a preconfigured LTI tool the course module cache for all LTI activities based on that preconfigured tool gets purged. The SQL query that gets the affected course module IDs joins two tables at the wrong column causing the same course module IDs to be returned multiple times. This leads to unnecessary many calls to \course_modinfo::purge_course_module_cache() which has to acquire a lock, read from the cache, and release the lock each time it is called for the same course module.

In our case this has lead to 1,287,389 calls to purge_course_module_cache() being made instead of "only" the 29,747 that are necessary.