# A problem of parallel processing in paraview
**URL:** https://discourse.paraview.org/t/a-problem-of-parallel-processing-in-paraview/5089
**Category:** ParaView Support
**Created:** [August 12, 2020, 4:31am UTC](https://discourse.paraview.org/t/a-problem-of-parallel-processing-in-paraview/5089 "2020-08-12T04:31:31Z")
**Posts on this page:** 10
**Page:** 1
### Author:  [@Jerry](https://discourse.paraview.org/u/Jerry)
#### Post date: [August 12, 2020, 4:31am UTC](https://discourse.paraview.org/t/a-problem-of-parallel-processing-in-paraview/5089/1 "2020-08-12T04:31:31Z")
I have made two machines as a remote server. And it seemed work good when I put something from the Sources menu.
But when I put something from other place, the parallel processing don’t work.
There is only one color rendered in the bunny and I can’t tell if there is only one cpu work for rendering it.
Do you have any idea of this problem??
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### Author:  [@utkarsh.ayachit](https://discourse.paraview.org/u/utkarsh.ayachit)
#### Post date: [August 12, 2020, 11:41am UTC](https://discourse.paraview.org/t/a-problem-of-parallel-processing-in-paraview/5089/2 "2020-08-12T11:41:47Z")
Certain readers, like OBJ reader, are not parallel-aware. In such cases, all data is generally read on the root node. You can then apply filters such as **Redistribute DataSet** (5.8 and newer) or **D3** (for earlier versions) to redistribute the dataset among all ranks.
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### Author:  [@Jerry](https://discourse.paraview.org/u/Jerry)
#### Post date: [August 13, 2020, 2:24am UTC](https://discourse.paraview.org/t/a-problem-of-parallel-processing-in-paraview/5089/3 "2020-08-13T02:24:01Z")
Thank you! My problem partly solved. I can apply **D3** for redistribute the dataset like this, 
but when I use **Redistribute DataSet** (and my paraview version is 5.8.0), it will be a connection refused like this, 
and I have no idea about it.
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### Author:  [@utkarsh.ayachit](https://discourse.paraview.org/u/utkarsh.ayachit)
#### Post date: [August 13, 2020, 10:40am UTC](https://discourse.paraview.org/t/a-problem-of-parallel-processing-in-paraview/5089/4 "2020-08-13T10:40:49Z")
I am not sure what that is. Looks like it’s coming from OpenMPI code. Is it causing any issues? Maybe try updating to a newer version of OpenMPI, if possible. You can simply continue to use **D3** in 5.8.
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### Author:  [@kirit\_101](https://discourse.paraview.org/u/kirit_101)
#### Post date: [August 25, 2020, 6:00pm UTC](https://discourse.paraview.org/t/a-problem-of-parallel-processing-in-paraview/5089/5 "2020-08-25T18:00:27Z")
Does CONVERGECFD reader not parallel-aware ?
I had a state file (\*.py) prepared using non-MPI ParaView, when I was trying to run this in a MPI ParaView version, it was crushing. is this the reason ?
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### Author:  [@utkarsh.ayachit](https://discourse.paraview.org/u/utkarsh.ayachit)
#### Post date: [August 25, 2020, 6:09pm UTC](https://discourse.paraview.org/t/a-problem-of-parallel-processing-in-paraview/5089/6 "2020-08-25T18:09:01Z")
From the [docs](https://vtk.org/doc/nightly/html/classvtkCONVERGECFDReader.html), it seems it does not support loading data in parallel.
cc: @cory.quammen
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### Author:  [@cory.quammen](https://discourse.paraview.org/u/cory.quammen)
#### Post date: [August 25, 2020, 6:12pm UTC](https://discourse.paraview.org/t/a-problem-of-parallel-processing-in-paraview/5089/7 "2020-08-25T18:12:48Z")
Indeed, the CONVERGECFD does not read in parallel.
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### Author:  [@kirit\_101](https://discourse.paraview.org/u/kirit_101)
#### Post date: [August 26, 2020, 4:17pm UTC](https://discourse.paraview.org/t/a-problem-of-parallel-processing-in-paraview/5089/8 "2020-08-26T16:17:57Z")
Thanks @utkarsh.ayachit, @cory.quammen.
In my state file ( prepared in for non-mpi version), I have added below line beginning of the pipeline :
redistributeDataSet1 = RedistributeDataSet(registrationName=‘RedistributeDataSet1’, Input=venturi\_data)
my expectation was I will be able to load this state file. Looks like its just stuck, not have any error message.
Is there anything else I need to add ?
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### Author:  [@cory.quammen](https://discourse.paraview.org/u/cory.quammen)
#### Post date: [August 28, 2020, 1:51am UTC](https://discourse.paraview.org/t/a-problem-of-parallel-processing-in-paraview/5089/9 "2020-08-28T01:51:20Z")
You shouldn’t need to add anything. If you can provide more details about your workflow that is leading to the hang, that would be helpful.
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### Author:  [@kirit\_101](https://discourse.paraview.org/u/kirit_101)
#### Post date: [September 1, 2020, 6:48pm UTC](https://discourse.paraview.org/t/a-problem-of-parallel-processing-in-paraview/5089/10 "2020-09-01T18:48:34Z")
thanks @cory.quammen.
In attachment there are two state files. MPI\_Test\_01.py was my older state file, created in non-MPI version of Paraview. To use this code in MPI version I modified MPI\_Test\_01.py the code to MPI\_Test\_02.py. You will see in line 69, I have added redistributeDataSet filter.
When I use the MPI\_code\_02.py, Paraview GUI crashed without giving any error message.
Attachments:
[MPI\_Test\_01.py](https://discourse.paraview.org/uploads/short-url/tfXbQXS9E1F2wmZbE9Qwr26gTNI.py) (25.7 KB) [MPI\_Test\_02.py](https://discourse.paraview.org/uploads/short-url/gdf8VBtJUhc7MYfG9osWxBhU47y.py) (25.8 KB)