Memory usage by subsystem

*Notice:

1. MemTracker only counts the memory on part of the main execution path, which is usually less than the real process memory.

2. each `type` is the sum of a set of tracker values, `sum of all trackers` is the sum of all trackers of all types, .

3. `process resident memory` is the physical memory of the process, from /proc VmRSS VmHWM.

4. `process virtual memory` is the virtual memory of the process, from /proc VmSize VmPeak.

5.`/mem_tracker?type=` to view the memory details of each type, for example, `/mem_tracker?type=query` will list the memory of all queries; `/mem_tracker?type=global` will list the memory of all Cache, metadata and other global life cycles.

see documentation for details.

Type	Label	Parent Label	Limit	Current Consumption(Bytes)	Current Consumption(Normalize)	Peak Consumption(Bytes)	Peak Consumption(Normalize)
experimental			none	0	0K	0	0K
clone			none	0	0K	0	0K
schema_change			none	0	0K	0	0K
compaction			none	0	0K	1652240576	1575M,716K
load			none	648992576	618M,949K	4809764704	4G,490M,971K
query			none	0	0K	4709964960	4G,395M,791K
global			none	17549962	16M,754K	5671400012	5G,288M,684K
tc/jemalloc cache			none	624947112	595M,1019K	-1	-1K
sum of all trackers			none	1291489650	1231M,676K	-1	-1K
process resident memory			none	5381222400	5G,11M,956K	9892638720	9G,218M,364K
process virtual memory			none	60541120512	56G,392M,524K	60608524288	56G,456M,812K