Since upgrading one of our production cluster from 6.2.4 to 6.3.1 , the monitoring systems showing all Request Cache Stats as zeros, including cache size/hit/miss/evict ,etc. These stats are collected from node stats api and I verified the stats by manually calling the api which gives me the same result.
I am sure we constantly have queries that involve Request Cache actions and all stats remaining at zero makes no sense. What I am not sure however is if there there is possibly a bug within the cache module or monitoring module?
Any advice is high appreciated!