[QGIS-Developer] Processing plugin algorithm slows down in graphical modeler

[Clemens Raffler]

Dear QGIS Devs,

Recently, I received two messages from users concerning the speed of 
processing algorithms which are implemented in the QNEAT3 plugin. More 
specifically, they report that the execution time of algorithms slow 
down up to 10 times when the algorithm is used in the graphical modeler 
compared to manual execution from the processing toolbox (used 
algorithm: OD Matrix from Layers as Lines (m:n)). I link the ticket from 
the QNEAT3 repository here for reference: 
https://github.com/root676/QNEAT3/issues/21

I would like to identify the cause of this problem because on the first 
look I can't relate it to any implementation flaws on the plugin side. 
Has anyone else experienced this problem with other processing plugins 
or core algorithms? I didn't have time yet to check if core algorithms 
are affected too. Could it be some kind of bug related to the graphical 
modeler? Do you have any hints what could cause this problem on the 
plugin side so I can fix it? Tanks in advance!

Best regards,
Clemens