# Why is JOIN function so slow?

**URL:** <https://resource.dopus.com/t/why-is-join-function-so-slow/4189>\
**Category:** Help & Support\
**Created:** [June 30, 2007, 2:21pm UTC](https://resource.dopus.com/t/why-is-join-function-so-slow/4189 "2007-06-30T14:21:09Z")\
**Posts on this page:** 1\
**Showing post:** 1

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**Author:** ![leo42](https://resource.dopus.com/letter_avatar_proxy/v4/letter/l/f0a364/32.png) [@leo42](https://resource.dopus.com/u/leo42)\
**Post date:** [June 30, 2007, 2:21pm UTC](https://resource.dopus.com/t/why-is-join-function-so-slow/4189/1 "2007-06-30T14:21:09Z")

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Hi,

I use the join function of DOpus, to join several files into one big files and I noticed it was quite slow. So I installed a tool dedicated to do that, and here are the results:

1. FFSJ 1.3.1: 34 sec
2. DOpus 9.0.6: 3min 37secs

All tests were performed on the same machine with the same files... To be sure this hadn't anything to do with cpu load, hd being fragmented,.. I did the tests with a clean harddrive, and did it several times.

I used files of 10Mb and the result file was about 400Mb

Does the copy buffer option found in DOpus prefs has an impact in the JOIN function ?

It's really too bad I have to rely on an external program to join files...

## Leo.

PS: If you want to do your own tests, FFSJ can be found here: [jaist.ac.jp/~hoangle/filesj/index.html](http://www.jaist.ac.jp/~hoangle/filesj/index.html) (I used the Lite version for the tests)

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