# Paraview 5.9.1 ghostCells
**URL:** https://discourse.paraview.org/t/paraview-5-9-1-ghostcells/8807
**Category:** Development
**Created:** [January 20, 2022, 3:05pm UTC](https://discourse.paraview.org/t/paraview-5-9-1-ghostcells/8807 "2022-01-20T15:05:18Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@ThomasAC](https://discourse.paraview.org/u/ThomasAC)
#### Post date: [January 20, 2022, 3:05pm UTC](https://discourse.paraview.org/t/paraview-5-9-1-ghostcells/8807/1 "2022-01-20T15:05:18Z")
Hi,
we have a custom cxx reader plugin. When updating ParaView from v5.8.1 to v5.9.1, we ran some small tests to ensure that the plugin is still doing what its supposed to do.
I observed that when I load the same data file with v5.8.1 and v5.9.1 in parallel (in this case 2 processes) and compare the data in a SpreadSheetView the solution differs. The difference is that when using v5.9.1 the ghostCells are displayed such that the data occurs twice. Once as regular cell and once marked as vtkGhostType.
Any idea why cells marked as vtkGhostType appear in the SpreadSheetView for v5.9.1?
In the reader plugin, each process reads a subset of the data file and then creates a vtkUnstructuredGrid. At the process boundaries ghostCells are added and marked as DUPLICATE.
The vtkUnstructuredGrid is then added to a vtkMultiBlockDataSet, which is the output of the reader. The number of the vtkUnstructuredGrids created depends on the input data, in the present case there is only one vtkUnstructuredGrid.
Might it be related to changes in the vtkMultiblockDataSet as discussed here: [Deprecating MultiBlock datasets](https://discourse.paraview.org/t/deprecating-multiblock-datasets/4950)
Thanks!
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [January 20, 2022, 3:09pm UTC](https://discourse.paraview.org/t/paraview-5-9-1-ghostcells/8807/2 "2022-01-20T15:09:02Z")
maybe @Yohann_Bearzi can help
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### Author:  [@Yohann\_Bearzi](https://discourse.paraview.org/u/Yohann_Bearzi)
#### Post date: [January 20, 2022, 3:25pm UTC](https://discourse.paraview.org/t/paraview-5-9-1-ghostcells/8807/3 "2022-01-20T15:25:54Z")
This is very likely to be caused by the changes in `vtkMultiBlockDataSet`. `vtkDataTabulator` needs to make sure that ghosts are filtered out. I’ll create an issue.
Edit: here’s the [issue](https://gitlab.kitware.com/paraview/paraview/-/issues/21188)
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### Author:  [@Yohann\_Bearzi](https://discourse.paraview.org/u/Yohann_Bearzi)
#### Post date: [January 20, 2022, 3:48pm UTC](https://discourse.paraview.org/t/paraview-5-9-1-ghostcells/8807/4 "2022-01-20T15:48:58Z")
@ThomasAC I just tried a 5.8.1. build, and the ghost data appears twice as well in the spread sheet. Am I missing something?
Edit:
To reproduce:
- Run ParaView with 2 ranks
- Create a Wavelet, hit apply
- Load Threshold, hit apply
- Load Ghost Cells Generator, hit apply
- Open a Spread Sheet View
- Select Cell Data
- Click on `vtkGhostType` to sort ghost values in a decreasing order in the Spread Sheet View, you’ll see ghosts with a value equal to 1.
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### Author:  [@cory.quammen](https://discourse.paraview.org/u/cory.quammen)
#### Post date: [January 20, 2022, 5:54pm UTC](https://discourse.paraview.org/t/paraview-5-9-1-ghostcells/8807/5 "2022-01-20T17:54:11Z")
I reproduce what Yohann sees, but using 5.7.0.
We could add an option in the SpreadSheet view to not show ghost cells/points, but it seems the current behavior is the same as in past versions.
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### Author:  [@ThomasAC](https://discourse.paraview.org/u/ThomasAC)
#### Post date: [January 21, 2022, 1:02pm UTC](https://discourse.paraview.org/t/paraview-5-9-1-ghostcells/8807/6 "2022-01-21T13:02:29Z")
I checked with my 5.8.1 build again and indeed the ghost data appears twice, too. Not sure what I did to overlook them before.
An option to hide ghost cell data, also when writing to csv, would be helpful. Written data files could be made independent of the number of processes used then.
Regarding the migration from `vtkMultiBlockDataSet` to `vtkPartitionedDataSet` mentioned, should the reader be updated in the near future?
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### Author:  [@cory.quammen](https://discourse.paraview.org/u/cory.quammen)
#### Post date: [January 21, 2022, 6:06pm UTC](https://discourse.paraview.org/t/paraview-5-9-1-ghostcells/8807/7 "2022-01-21T18:06:04Z")
`vtkMultiBlockDataSet` will still be supported for at least the next ParaView release, but updating to `vtkPartitionedDataSetCollection` when you can is recommended.