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https://github.com/koraa/huniq

Filter out duplicates on the command line. Replacement for `sort | uniq` optimized for speed (10x faster) when sorting is not needed.
https://github.com/koraa/huniq

cli rust tools

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Filter out duplicates on the command line. Replacement for `sort | uniq` optimized for speed (10x faster) when sorting is not needed.

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# huniq version 2



Command line utility to remove duplicates from the given input.

Note that huniq does not sort the input, it just removes duplicates.



```

SYNOPSIS: huniq -h # Shows help

SYNOPSIS: huniq [-c|--count] [-0|--null|-d DELIM|--delim DELIM]

```



```

$ echo -e "foo\nbar\nfoo\nbaz" | huniq

foo

bar

baz



$ echo -e "foo\nbar\nfoo\nbaz" | huniq -c

1 baz

2 foo

1 bar

```



`huniq` replaces `sort | uniq` (or `sort -u` with gnu sort) and `huniq -c` replaces `sort | uniq -c`, assuming the data is sorted just so it can be passed to `uniq`. If having sorted output is desired, `sort | uniq` should still be used.



The order of the output is stable when in normal mode, but it is not stable when in -c/count mode.



## Installation



```

$ cargo install huniq

```



## Motivation



Sorting is slow. By using hash tables/hash sets instead of sorting

the input huniq is generally faster than `sort -u` or `sort | uniq -c` when testing with gnu sort/gnu uniq.



## Version History



Version 1 can be found [here](https://github.com/SoftwearDevelopment/huniq).



Changes made in version 2:



* The -d/-0 flags where added so you can specify custom delimiters

* Completely rewritten in rust.

* Version two is (depending on which benchmark you look at below) between 3.5x and 6.5x faster than version 1



## Build



```sh

cargo build --release

```



To run the tests execute:



```sh

bash ./test.sh

```



## Benchmark



You can use `bash ./benchmark.sh` to execute the benchmarks. They will execute until you manually abort them (e.g. by pressing Ctrl-C).



The benchmarks work by repeatedly feeding the implementations with data

from /usr/share/dict/* and measuring memory usage and time needed to process

the data with the unix `time` tool.



For the `uniq` algorithm, the results are posted below: We can see that the

rust implementation blows pretty much anything else out of the water in terms

of performance. Use sort only if you really need a coffee break, because you

won't get it with huniq! It beats the C++ implementation by a factor

of between 6.5 (for very few duplicates) and 3.5 (around 98% duplicates).

Compared to `sort -u`: huniq is around 30 times faster.



If memory efficiency is what you are looking for, use datamash which is not as fast as huniq

but uses the least memory (by a factor of around 3); failing that use `sort|uniq` which is a

lot slower but uses just very slightly more memory than datamash.



```

repetitions  implementation  seconds  memory/kb

1            huniq2-rust        0.26      29524

1            huniq1-c++         1.67      26188

1            awk                1.63     321936

1            datamash           1.78       9644

1            shell              7.30       9736

2            huniq2-rust        0.84      29592

2            huniq1-c++         3.28      26180

2            awk                3.71     322012

2            datamash           4.60       9636

2            shell             16.68       9740

5            huniq2-rust        2.02      29648

5            huniq1-c++         6.21      26184

5            awk                7.69     322012

5            datamash           9.10       9992

5            shell             44.71      10184

10           huniq2-rust        3.40      29676

10           huniq1-c++        12.84      26172

10           awk               16.73     321940

10           datamash          24.44      10032

10           shell             93.75      10036

50           huniq2-rust       14.68      29612

50           huniq1-c++        55.32      26200

50           awk               74.91     321940

50           datamash         103.54      10936

50           shell            453.94      10956

100          huniq2-rust       43.65      29492

100          huniq1-c++       154.99      26180

100          awk              239.66     321956

100          datamash         285.94      12148

100          shell           1062.07      12208

```



For the counting `huniq -c` implementation, the speed advantage

was less pronounced: Here the rust implementation is between 25%

and 50% faster than the C++ implementation and between 5x and 10x

faster than `sort | uniq -c`.



The increased memory usage of the rust implementation is much worse though:

The rust implementation needs about 2.2x more memory than the C++ implementation

and between 10x and 12x more memory than `sort | uniq`.



```

repetitions  implemetation  seconds  memory/kb

1            huniq2-rust       1.47     132096

1            huniq1-c++        1.85      60196

1            awk               2.79     362940

1            datamash          2.28       9636

1            shell             7.71      11716

2            huniq2-rust       2.32     132052

2            huniq1-c++        2.98      60156

2            awk               4.65     363016

2            datamash          5.27       9732

2            shell            16.37      11680

5            huniq2-rust       4.98     132092

5            huniq1-c++        7.54      60128

5            awk               9.37     363016

5            datamash         11.22       9964

5            shell            44.77      11948

10           huniq2-rust       8.81     132048

10           huniq1-c++       13.55      60196

10           awk              16.19     363032

10           datamash         25.12       9908

10           shell            90.01      11976

50           huniq2-rust      45.89     132092

50           huniq1-c++       74.04      60104

50           awk              85.43     362956

50           datamash        141.90      10996

50           shell           454.42      12876

100          huniq2-rust      90.80     132080

100          huniq1-c++      150.41      60196

100          awk             163.13     363008

100          datamash        322.70      12212

100          shell           933.67      14100

```



## Future direction



Feature wise huniq is pretty much complete, but the performance and memory usage should be improved in the future.



This first of all involves a better benchmarking setup which will probably consist

of an extra rust application that will use RNGs to generate test data for huniq and

take parameters like the number of elements to create, the rate of duplicates (0-1)

the length of strings to output and so on…



Then based on the improved benchmarking capabilities, some optimizations should be tried

like short string optimization, arena allocation, different hash functions, using

memory optimized hash tables, using an identity function for the `uniq` function

(we already feed it with hashes, so a second round of hashing is not necessary).



## License



Copyright © (C) 2020, Karolin Varner. All rights reserved.



Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:



    Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

    Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

    Neither the name of the Karolin Varner nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.



THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL Softwear, BV BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.