[QGIS-Developer] Question

[Marco Hugentobler]

Am 22.10.20 um 08:48 schrieb Raymond Nijssen:
> Hi Guillaume,
>
> A 5% progress after 5 days still sounds extremely slow! That would 
> take approximately 100 days to finish on 1 core, or 2 days (72 hours!) 
> on 32 cores.
>
> I don't know how large or complicated these shapefiles are, but you 
> might try to find the solution in another way.
>
> - Make sure you are using indexes?
> - Select non-overlapping shapes and delete them?
> - Split the files in parts?
> - Move to Postgis? (Am I allowed to suggest that here? ;) )
>
> @Marco Shouldn't that code end up in QGIS or is it still in your repo 
> for a reason?

I don't know the reason it was never merged. All the feedback has been 
addressed and the unit tests passed.

Regards,

Marco


>
> Kind regards,
> Raymond
>
>
>
>
> On 22-10-2020 07:20, Marco Hugentobler wrote:
>> Hi Guillaume
>>
>>
>>  >My question: Is there a way to take advantage of the fact that I 
>> have 32 cores on my computer with QGIS to make this calculation? I 
>> don't understand why it is so slow.
>>
>>
>> Yes, there is. Compile the code from the 
>> 'processing_multithreaded_vector' branch in my repo 
>> (https://github.com/mhugent/QGIS/tree/processing_multithreaded_vector). 
>> It calculates the difference operation on multiple cores (see also 
>> https://github.com/qgis/QGIS/pull/33365).
>>
>>
>> Regards,
>>
>> Marco
>>
>>
>> Am 22.10.20 um 03:05 schrieb guillaume martel:
>>> Hi,
>>>
>>> I don't know if I'm writing at the wrong place...
>>>
>>> I have 2 shapefiles and I want to do a "difference operation" 
>>> (https://docs.qgis.org/3.10/en/docs/user_manual/processing_algs/qgis/vectoroverlay.html). 
>>>
>>>
>>> My issue is as follow: Even though I have a powerful computer, after 
>>> 5 days the calculation is only at 5%.
>>>
>>> My question: Is there a way to take advantage of the fact that I 
>>> have 32 cores on my computer with QGIS to make this calculation? I 
>>> don't understand why it is so slow.
>>>
>>> Thank you for your help.
>>>
>>> Guillaume
>>>
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>>
>> -- 
>> Dr. Marco Hugentobler
>> Sourcepole -  Linux & Open Source Solutions
>> Weberstrasse 5, CH-8004 Zürich, Switzerland
>> marco.hugentobler at sourcepole.ch  http://www.sourcepole.ch
>>
>>
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-- 
Dr. Marco Hugentobler
Sourcepole -  Linux & Open Source Solutions
Weberstrasse 5, CH-8004 Zürich, Switzerland
marco.hugentobler at sourcepole.ch http://www.sourcepole.ch