Multi-threaded sorting of text file

Ali Çehreli acehreli at yahoo.com
Sun Jan 5 04:01:27 UTC 2020


On 1/3/20 11:51 PM, MGW wrote:
> Need help:
> There' s a large text file (hundreds of thousands of lines).

How long are the lines? If 1K bytes, 100M would fit in memory just fine. 
There is a parallel quick sort example on the std.parallelism page:

   https://dlang.org/phobos/std_parallelism.html

> The structure is as follows:
> 2345|wedwededwedwedwe ......
> 872625|rfrferwewweww .....
> 23|rergrferfefer ....
> .................
> 
> It is necessary to sort this file by the first field having received:
> 23|rergrferfefer.......
> 2345|wedwededwedwedwe.......
> 872625|rfrferwewweww.......

Are you going to write the result back to a file? Then you would hardly 
notice any improvement from parallelism because relative slowness of I/O 
would determine the overall performance.

> 
> There are also N CPU (from 4 to 8) and 16 Gb of Memory. Necessary
> come up with an algorithm in D for fast sorting using multithreading.
> 
> 

Ali


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