# Show cached tasks in nextflow run preview

**URL:** <https://community.seqera.io/t/show-cached-tasks-in-nextflow-run-preview/1493>\
**Category:** Ask for help\
**Tags:** nextflow\
**Created:** [November 25, 2024, 4:51pm UTC](https://community.seqera.io/t/show-cached-tasks-in-nextflow-run-preview/1493 "2024-11-25T16:51:16Z")\
**Posts on this page:** 1\
**Showing post:** 3

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**Author:** ![Gullumluvl](https://dub1.discourse-cdn.com/flex013/user_avatar/community.seqera.io/gullumluvl/32/1050_2.png) [@Gullumluvl](https://community.seqera.io/u/Gullumluvl)\
**Post date:** [December 3, 2024, 4:39pm UTC](https://community.seqera.io/t/show-cached-tasks-in-nextflow-run-preview/1493/3 "2024-12-03T16:39:37Z")

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Thanks.

Wouldn’t it be a useful feature?

I have been very enthusiastic about Nextflow since I started 3 months ago, however at the moment I have one big problem with it, which is how to deal with the caching mechanism. I end up involuntarily restarting many time-consuming tasks because of this.

More precisely:

1. I think a less strict criterion for resuming would be useful. Possible solutions:
  - a configuration option to loosen it, like `cache = "filenames+timestamp"`
  - a way to prevent relaunching processes with a specific name.

2. In the absence of the above point, a way to predict caching/resuming _without_ executing any process. The `-preview` option seems like the most natural option to enhance with this.

Based on my recent experience, examples of modifications to processes that prevented resuming:

- removing one of the files from the output. E.g. from:

- adding input/output `val` that don’t impact the executed command, for example to [pass metadata](https://community.seqera.io/t/process-input-that-is-not-cached-and-does-not-affect-task-hash/1209).

- adding line returns, other whitespaces, or reorder arguments in a way should not change the result of the script block. This might be impossible to detect programmatically which is why a looser criterion for resuming would be nice.

- Many ones where I don’t have an explanation, for example I currently have this _independent_ block in a workflow which got entirely restarted (222 long-running processes):

I’d like to know what you and other developers at Nextflow think. Actually I would imagine a similar request has already been made.

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_[View the full topic](https://community.seqera.io/t/show-cached-tasks-in-nextflow-run-preview/1493)._