# How to speed up the selection of arrays for reading?

**URL:** https://discourse.paraview.org/t/how-to-speed-up-the-selection-of-arrays-for-reading/3074
**Category:** ParaView Support
**Created:** [November 29, 2019, 10:11am UTC](https://discourse.paraview.org/t/how-to-speed-up-the-selection-of-arrays-for-reading/3074 "2019-11-29T10:11:23Z")
**Posts on this page:** 4
**Page:** 1

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### Author: ![e-kolosov](https://discourse.paraview.org/user_avatar/discourse.paraview.org/e-kolosov/32/2375_2.png) [@e-kolosov](https://discourse.paraview.org/u/e-kolosov)
#### Post date: [November 29, 2019, 10:11am UTC](https://discourse.paraview.org/t/how-to-speed-up-the-selection-of-arrays-for-reading/3074/1 "2019-11-29T10:11:24Z")

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Hello.  
In the reader, I use vtkDataArraySelection and the following xml description: [arrays\_selection.xml](https://discourse.paraview.org/uploads/short-url/9fbq94A8nzVV5TIlSVFpVb5oPqn.xml) (943 Bytes)  
vtkDataArraySelection contains 10k array names and I want to mark 1k of them for reading. This action, which only marks the array names as “true”, takes more than 15 minutes.  
What am I doing wrong? How to speed up the selection of arrays for reading?  
Thanks in advance.

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### Author: ![mwestphal](https://discourse.paraview.org/user_avatar/discourse.paraview.org/mwestphal/32/17_2.png) [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [November 29, 2019, 10:40am UTC](https://discourse.paraview.org/t/how-to-speed-up-the-selection-of-arrays-for-reading/3074/2 "2019-11-29T10:40:20Z")

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Which action is taking 15 minutes ? Setting the property ? When you click on Apply ?

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### Author: ![e-kolosov](https://discourse.paraview.org/user_avatar/discourse.paraview.org/e-kolosov/32/2375_2.png) [@e-kolosov](https://discourse.paraview.org/u/e-kolosov)
#### Post date: [November 29, 2019, 11:28am UTC](https://discourse.paraview.org/t/how-to-speed-up-the-selection-of-arrays-for-reading/3074/3 "2019-11-29T11:28:54Z")

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Before clicking the “Apply” button of course. 15 minutes is the time it took to switch on the checkboxes. This is the time between steps 2 and 3 (see pictures)

 ![select_arrays1](https://discourse.paraview.org/uploads/default/original/2X/b/b4ae662b3a7e98f7ab46a76b09c60d7e31b9047e.png)  
 ![select_arrays2](https://discourse.paraview.org/uploads/default/original/2X/2/287878d3ad2771acfed165a9e8c39da2cba3a5e2.png)

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### Author: ![mwestphal](https://discourse.paraview.org/user_avatar/discourse.paraview.org/mwestphal/32/17_2.png) [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [November 29, 2019, 12:04pm UTC](https://discourse.paraview.org/t/how-to-speed-up-the-selection-of-arrays-for-reading/3074/4 "2019-11-29T12:04:07Z")

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Clearly, the typical number of Arrays is more in the dozen, not in the thousands. In the context of developing a plugin, you may be able to develop your own domain using a more efficient algo.