# .pvd reload only modified files
**URL:** https://discourse.paraview.org/t/pvd-reload-only-modified-files/4577
**Category:** ParaView Support
**Created:** [June 14, 2020, 11:23pm UTC](https://discourse.paraview.org/t/pvd-reload-only-modified-files/4577 "2020-06-14T23:23:32Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@particleincell](https://discourse.paraview.org/u/particleincell)
#### Post date: [June 14, 2020, 11:23pm UTC](https://discourse.paraview.org/t/pvd-reload-only-modified-files/4577/1 "2020-06-14T23:23:32Z")
I am currently using a .pvd file to group a large number of 2D .vti data sets. (This is not really important, but the y-axis in each is time, and the individual files are offset such that when loaded together, we get time history of some 1D data.) My code basically outputs a new .vti file every so many time steps, and updates the .pvd to include this additional data set. I use the “Reload Files” option on the .pvd file to monitor my simulation. The problem is that this reload takes forever. Is there some way to make a .pvd data set act like Linux Makefile, so that only modified files get reloaded?
My .pvd file looks like this:
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Thanks!
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [June 15, 2020, 3:32am UTC](https://discourse.paraview.org/t/pvd-reload-only-modified-files/4577/2 "2020-06-15T03:32:54Z")
There must be a filter that needs all timesteps to be able to compute in your pipeline.
Can you share your pipeline ?
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### Author:  [@particleincell](https://discourse.paraview.org/u/particleincell)
#### Post date: [June 15, 2020, 3:37am UTC](https://discourse.paraview.org/t/pvd-reload-only-modified-files/4577/3 "2020-06-15T03:37:41Z")
I literally just visualize the pvd directly as a surface (it’s a collection of 2D vtis). All files are listed as the same timestep, however, since I am effectively trying to build a larger dataset from pieces. Perhaps a different file format is more suitable but the documentation I could find is quite sparse.
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [June 15, 2020, 3:40am UTC](https://discourse.paraview.org/t/pvd-reload-only-modified-files/4577/4 "2020-06-15T03:40:33Z")
Ok, I’m afraid reload does not do what you want and load everything again. It has no way to determine that a specific .vti has not changed.
In you case you should read the .vti file directly by creating a new reader each time and group them together.
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### Author:  [@particleincell](https://discourse.paraview.org/u/particleincell)
#### Post date: [June 15, 2020, 4:08am UTC](https://discourse.paraview.org/t/pvd-reload-only-modified-files/4577/5 "2020-06-15T04:08:44Z")
How do you suggest to do this? There are around 100 files at the end, but the number varies as the simulation runs. But anyway, that’s why I mentioned the Makefile example. You could just check the file timestamp and ignore if the same as currently loaded.
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [June 15, 2020, 4:09am UTC](https://discourse.paraview.org/t/pvd-reload-only-modified-files/4577/6 "2020-06-15T04:09:49Z")
Sadly , reload file doesn’t do that.
You should write a pvpython script to do this task.
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### Author:  [@particleincell](https://discourse.paraview.org/u/particleincell)
#### Post date: [June 15, 2020, 8:25pm UTC](https://discourse.paraview.org/t/pvd-reload-only-modified-files/4577/7 "2020-06-15T20:25:09Z")
Ok, thank you for getting back to me. Anyway, this may be a useful feature to add in the future in general - there shouldn’t be any need to reload files if time stamps are the same as in memory (not dirty).
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [June 16, 2020, 1:08am UTC](https://discourse.paraview.org/t/pvd-reload-only-modified-files/4577/8 "2020-06-16T01:08:35Z")
I agree that it would be nice to have this as an options. Could you open an issue on our gitlab :
[https://gitlab.kitware.com/paraview/paraview/-/issues](https://gitlab.kitware.com/paraview/paraview/-/issues)