The loading of the field layout cache is not properly synchronized, leading to major performance issues for large customers with many custom fields.

The loading of the field layout cache is not properly synchronized, leading to major performance issues for large customers with many custom fields.

Because the reloading of the cache is not synchronized, when a large number of requests arrive more or less simultaneously they all try and initialize the cache simultaneously. This is exacerbated by the fact that a dashboard may contain a number of filter results which will each try and reload the cache in parallel.
The end result is a complete overloading of the system. You can see from the attached thread dump over 100 different requests all trying to load the field layout cache simultaneously.