···

       
8
       
8
       
 
       
<img src="1brc.png" alt="1BRC" style="display: block; margin-left: auto; margin-right: auto; margin-bottom:1em; width: 50%;">

     

       
9
       
9
       
 
       


     

       
10
       
10
       
 
       
The text file contains temperature values for a range of weather stations.

     

       
11
       
11
       
-
       
Each row is one measurement in the format `<string: station name>;<double: measurement>`.

     

       
11
       
11
       
+
       
Each row is one measurement in the format `<string: station name>;<double: measurement>`, with the measurement value having exactly one fractional digit.

     

       
12
       
12
       
 
       
The following shows ten rows as an example:

     

       
13
       
13
       
 
       


     

       
14
       
14
       
 
       
```

     
···

       
132
       
132
       
 
       
Each contender will be run five times in a row.

     

       
133
       
133
       
 
       
The slowest and the fastest runs are discarded.

     

       
134
       
134
       
 
       
The mean value of the remaining three runs is the result for that contender and will be added to the results table above.

     

       
135
       
135
       
+
       
The exact same _measurements.txt_ file is used for evaluating all contenders.

     

       
135
       
136
       
 
       


     

       
136
       
137
       
 
       
If you'd like to spin up your own box for testing on Hetzner Cloud, you may find these [set-up scripts](https://github.com/gunnarmorling/cloud-boxes/) (based on Terraform and Ansible) useful.

     

       
137
       
138
       
 
       
Note this will incur cost you are responsible for, I am not going to pay your cloud bill :)

     
···

       
150
       
151
       
 
       
A: No, this challenge is focussed on Java only. Feel free to inofficially share interesting implementations and results though. For instance it would be interesting to see how DuckDB fares with this task.

     

       
151
       
152
       
 
       


     

       
152
       
153
       
 
       
_Q: Can I use JNI?_\

     

       
153
       
153
       
-
       
A: Submissions must be implemented in Java; JNI requires glue code written in C/C++, so it cannot be used. You could use AOT compilation of Java code via GraalVM though, either by AOT-compiling the entire application, or by creating a native library which you then invoke using the new Java FFI (https://openjdk.org/jeps/442[JEP 442]).

     

       
154
       
154
       
+
       
A: Submissions must be completely implemented in Java, i.e. you cannot write JNI glue code in C/C++. You could use AOT compilation of Java code via GraalVM though, either by AOT-compiling the entire application, or by creating a native library (see [here](https://www.graalvm.org/22.0/reference-manual/native-image/ImplementingNativeMethodsInJavaWithSVM/).

     

       
154
       
155
       
 
       


     

       
155
       
156
       
 
       
_Q: What is the encoding of the measurements.txt file?_\

     

       
156
       
157
       
 
       
A: The file is encoded with UTF-8.