# 1️⃣🐝🏎️ The One Billion Row Challenge -- C# Edition -- nietras

• See https://github.com/gunnarmorling/1brc for original Java challenge.
• See https://huggingface.co/datasets/nietras/1brc.data for data only.

For command line process start/stop measurement https://github.com/sharkdp/hyperfine is used. This can be installed with Chocolatey (or WinGet):

choco install hyperfine

2024-01-15 (comparison by @buybackoff see https://hotforknowledge.com/2024/01/13/7-1brc-in-dotnet-even-faster-than-java-cpp/#results)

2024-01-14 (comparison by @xoofx see https://mastodon.social/@xoofx/111755470365432385 note ~800 are in ms)

2024-01-13 (comparison by me)

Data Statistics for One Billion Row Challenge

1BRC numbers for 1B rows data file. 413 station names. Length = Unique Count.

 3 =  2
 4 = 18
 5 = 42
 6 = 87
 7 = 66
 8 = 57
 9 = 47
10 = 26
11 = 26
12 = 17
13 =  9
14 =  4
15 =  2
16 =  6
17 =  1
18 =  1
24 =  1
26 =  1

Note how all lie within first 32 bytes. Optimise for that. Only 4/413 are longer than 16 bytes, so 1% only. Optimize for that. Keep in mind length=16 cannot be found by Vector128. In any case, doing one Vector256 search is faster than two Vector128 searches. 32 - 26 = 6. Longest number is -99.9 or 5 bytes so most line endings will be found within this too. Optimize for that. Handle remaining 1% with a fallback still fast but not as fast.

Besides the official 1BRC data file there is an extended 1B rows 10000 real station names of 1-99 length (via create_measurements3.sh). That some also use for benchmarking and testing. This is different since it is heavily weighted towards short station names.

  1 =   109
  2 =   328
  3 =  3260
  4 =  3252
  5 =   369
  6 =   196
  7 =   166
  8 =   144
  9 =   111
 10 =    99
 11 =    77
 12 =    88
 13 =    76
 14 =    61
 15 =    52
 16 =    51
 17 =    51
 18 =    49
 19 =    61
 20 =    35
 21 =    50
 22 =    33
 23 =    35
 24 =    25
 25 =    28
 26 =    30
 27 =    29
 28 =    17
 29 =    27
 30 =    39
 31 =    27
 32 =    25
 33 =    22
 34 =    26
 35 =    21
 36 =    14
 37 =    34
 38 =    12
 39 =    16
 40 =    22
 41 =    19
 42 =    25
 43 =    25
 44 =    18
 45 =    20
 46 =    14
 47 =    22
 48 =    12
 49 =    18
 50 =    20
 51 =    20
 52 =    21
 53 =    23
 54 =    16
 55 =    23
 56 =    17
 57 =     8
 58 =    13
 59 =    16
 60 =    13
 61 =    10
 62 =    19
 63 =     7
 64 =    17
 65 =    23
 66 =    18
 67 =    12
 68 =    18
 69 =    11
 70 =    17
 71 =    10
 72 =    12
 73 =    13
 74 =    10
 75 =    15
 76 =    11
 77 =    15
 78 =    18
 79 =    10
 80 =    11
 81 =    11
 82 =    12
 83 =    12
 84 =    15
 85 =     6
 86 =    13
 87 =    10
 88 =    10
 89 =     5
 90 =    12
 91 =    12
 92 =    11
 93 =    12
 94 =    14
 95 =    10
 96 =    10
 97 =    10
 98 =     6
 99 =     2

⚠ An implementation should not only handle the above and the specific station names, but pass a set of tests that cover all possible uses. Hence, above statistics are only used for optimizing the hot path not to only handle that.

BrcTest.cs runs and passes all the tests specified by the challenge for this C#/.NET 8 version.