sergey-dryabzhinsky
commented
3 years ago It's safe to use -100 level, at least since 1.4.5. Tested on 12Mb SQL-dump. Speed is greate but ratio is suck.
Compression
Table of ratio in %:
level zstd zlib
-100 63.74
-50 52.61
-20 35.06
-10 28.78
-5 25.64
-4 25.10
-3 24.73
-2 24.16
-1 23.78
1 17.68 21.80
2 17.88 21.15
3 17.67 20.54
4 18.40 19.19
5 17.73 18.27
6 16.99 17.92
7 16.68 17.76
8 16.54 17.58
9 16.46 17.58
10 16.41
11 16.32
12 16.30
13 15.87
14 14.79
15 14.33
16 14.17
17 14.14
18 14.12
19 14.08
20 14.06
Table of speed in Mb/s:
level zstd zlib
-100 990.98
-50 829.71
-20 604.65
-10 544.87
-5 486.82
-4 473.44
-3 457.86
-2 438.94
-1 421.48
1 371.45 122.09
2 338.99 108.41
3 248.63 91.23
4 249.55 77.87
5 149.08 60.91
6 97.56 42.00
7 80.16 32.16
8 62.31 15.40
9 45.51 13.40
10 33.03
11 22.90
12 17.58
13 13.64
14 9.66
15 6.86
16 5.05
17 3.64
18 2.16
19 2.04
20 1.12 Decompression
Table of speed in Mb/s:
level zstd zlib
-100 2793.54
-50 1918.92
-20 1364.04
-10 1312.15
-5 1234.27
-4 1206.13
-3 1184.73
-2 1172.13
-1 1145.40
1 1021.16 323.78
2 930.12 328.26
3 998.95 335.72
4 902.10 329.63
5 890.62 334.98
6 920.96 336.79
7 981.44 331.95
8 1021.53 340.58
9 1031.44 337.56
10 1045.02
11 1032.52
12 1021.93
13 1026.44
14 1068.57
15 1100.77
16 1060.96
17 1047.56
18 1038.88
19 1042.81
20 1047.33
As on Zstandard page in comparison table - it may be 7 or probably even 100. Research and Discussion needed.