Server memory usage is too high

server| used mem| total mem| used % |instance |mem used /instance
10.xx.xx.xx 15.4 15.55 99 1 15.4
11.xx.xx.xx 15.4 15.55 99 1 15.4
12.xx.xx.xx 15.4 15.55 99 1 15.4
13.xx.xx.xx 15.4 15.55 99 1 15.4
14.xx.xx.xx 15.4 15.55 99 1 15.4
15.xx.xx.xx 13.65 15.55 88 1 13.65
16.xx.xx.xx 54.49 62.88 87 6 9.08
17.xx.xx.xx 13.06 15.55 84 1 13.06
18.xx.xx.xx 13.08 15.55 84 1 13.08
19.xx.xx.xx 12.9 15.55 83 1 12.9
20.xx.xx.xx 49.92 62.91 79 3 16.64
21.xx.xx.xx 49.92 62.91 79 3 16.64
22.xx.xx.xx 49.95 62.9 79 3 16.65
23.xx.xx.xx 23.73 31.42 76 2 11.87
24.xx.xx.xx 35.62 47.16 76 3 11.87
25.xx.xx.xx 35.63 47.16 76 3 11.88
26.xx.xx.xx 31.85 47.1 68 3 10.62
27.xx.xx.xx 29.81 47.09 63 3 9.94
28.xx.xx.xx 29.87 47.09 63 3 9.96
29.xx.xx.xx 19.44 31.42 62 2 9.72
30 xx.xx.xx 74.98 126.01 60 6 12.5
31.xx.xx.xx 27.9 47.09 59 3 9.3
32.xx.xx.xx 18.22 31.19 58 2 9.11
33.xx.xx.xx 18.22 31.19 58 2 9.11
34.xx. xx.xx 72.57 126.02 58 6 12.1
35.xx.xx.xx 27.46 47.1 58 3 9.15
36.xx.xx.xx 26.5 47.1 56 3 8.83
37.xx.xx.xx 43.45 126.02 34 6 7.24
38.xx.xx. xx 17.71 126.01 14 1 17.71

Memory measurement unit: G
It seems to be regular:
large memory, multi-instance server, memory usage per instance, relatively small,
small memory, server with few instances, memory usage per instance , relatively high.
The reason may be that after the instantaneous memory rises, the memory is insufficient, and a lot of garbage collection and virtual memory are used, and eventually all the memory cannot be released.