I have a tough nut to crack,MEM information stored in the infuxdb database,There are cached columns and buffered and used columns and free columns and total columns,The Linux system reads and writes caching mechanisms that treat the cache and buffer parts of memory as available memory.
Because the environment is running in a special program, the cache part is not available,Therefore, monitoring should also follow the adjustment,Treat the cache part of memory as an unusable part.
but,In grafana Such SQL statements are not supported：
select mean（cached+buffered+used）/total*100 from mem where host=‘hostA’ or host=‘hostB’ AND $timeFilter group by time($interval) fil(null) #(Calculates the percentage of memory usage for multiple hosts)
Can you help me with the problem of this statement?