What can cause a full system cache flushIssue This article explains what can cause a full system cache flush. The instance can be slow after a cache flush. This can also be translated in high response time, coupled with default semaphore exhaustion on all nodes: HTTP 429 errors (too many requests).ReleaseAll releasesResolutionA full system cache flush means that all transactions have to pull their data from the database, and this makes them slower than when the cache has been rebuilt. Cache flush can be triggered by, but not limited to: a) Instance Upgradesb) Installing Pluginsc) Deploying Update Setsd) Making Property Changes (On Properties that don't have the 'ignore cache' check box checked)e) Executing the link: https://[instance_name].service-now.com/cache.dof) Instance Restartsg) Running the script gs.cacheFlush(); on /sys.scripts.do, or business rule, or script_include...etc We advise you not to perform this action during core business hours if possible.