Billion Row Challenge in Go

Inspired by https://github.com/gunnarmorling/1brc

The challenge is to write a Go program which reads measurements.txt, calculates the min, mean, and max temperature value per weather station, and emits the results on stdout in the format <station>=<min>/<mean>/<max> for each station, separated by a newline. The stations must be ordered alphabetically.

The following shows an example of measurements.txt:

Hamburg;12.0
Bulawayo;8.9
Palembang;38.8
St. John's;15.2
Cracow;12.6
Bridgetown;26.9
Istanbul;6.2
Roseau;34.4
Conakry;31.2
Istanbul;23.0

You can generate a sample measurements.txt with go run generate.go <num-measurement>.

Once a measurements.txt file is created, you can run the sample submission with go run baseline.go.

Rules

• No external library dependencies may be used
• The computation must happen at application runtime, i.e. you cannot process the measurements file at build time and just bake the result into the binary
• Input value ranges are as follows:
• Station name: non null UTF-8 string of min length 1 character and max length 100 characters
• Temperature value: non null double between -99.9 (inclusive) and 99.9 (inclusive), always with one fractional digit
• There is a maximum of 10,000 unique station names
• Implementations must not rely on specifics of a given data set, e.g. any valid station name as per the constraints above and any data distribution (number of measurements per station) must be supported

Submissions

Submit your submission as a PR to this repository by January 31, 2024. Your submission should be a single source file with your name or Github username, e.g., alice.go.

Evaluation

Submissions will be tested on a Macbook Pro with M1 Pro and 32GB of memory. Go 1.21 will be used. Each submission will compiled and run once to ensure correctness. Then it will be run five times with the time program to track the runtime. The highest and lowest times will be discarded, and the remaining three will be averaged for a final result.

Leaderboard