<p>I have the following Nextflow script:</p>
<pre><code>nextflow.enable.dsl=2
include { check_folders; downloadClinvar; downloadReferenceGenome; downloadBedFiles; downloadGatkVcfFiles } from '/home/user/Desktop/pipeline/download_data.nf'
workflow {
    check_folders()
    downloadClinvar(check_folders.out)
    downloadReferenceGenome(check_folders.out)
    downloadBedFiles(check_folders.out)
    downloadGatkVcfFiles(check_folders.out)
}
</code></pre>
<p>The graph that is generated for me using the -preview -with-dag flags is the following:
<a href="https://i.sstatic.net/wHad8xY8.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/wHad8xY8.png" alt="enter image description here" /></a></p>
<p>When I run the workflow it works fine but it performs each step sequentially, and I want it to download everything at the same time.</p>
<p>What could be happening to me? Why is my nextflow script executed sequentially?</p>

CC BY-SA 4.0
2024-05-08T08:34:39.583Z
Cross-postd https://stackoverflow.com/questions/78445082/why-is-my-nextflow-script-executed-sequentially
ATpoint
CC BY-SA 4.0
2024-05-08T14:19:41.217Z
Does the machine you run on have sufficient resources to run these processes in parallell?
Pallie
CC BY-SA 4.0
2024-05-09T10:20:15.203Z
Yes Pallie, I have Intel i8 7th generation, with 16GB of RAM
MauriRamone
CC BY-SA 4.0
2024-05-14T08:40:32.987Z
If your processes request a large amount of RAM/processors per process, that still could be the reason you're not getting parallellised processes
Pallie
<nextflow><workflow-management>
Why is my nextflow script executed sequentially?
# Why is my nextflow script executed sequentially?

(Asked by: username_0 on 2024-05-07)

I have the following Nextflow script:
nextflow.enable.dsl=2
include { check_folders; downloadClinvar; downloadReferenceGenome; downloadBedFiles; downloadGatkVcfFiles } from '/home/user/Desktop/pipeline/download_data.nf'
workflow {
    check_folders()
    downloadClinvar(check_folders.out)
    downloadReferenceGenome(check_folders.out)
    downloadBedFiles(check_folders.out)
    downloadGatkVcfFiles(check_folders.out)
}

The graph that is generated for me using the -preview -with-dag flags is the following:

When I run the workflow it works fine but it performs each step sequentially, and I want it to download everything at the same time.
What could be happening to me? Why is my nextflow script executed sequentially?

**Tags:** nextflow, workflow-management
> **Comments:**
> **username_1**: Cross-postd https://stackoverflow.com/questions/78445082/why-is-my-nextflow-script-executed-sequentially  
> **username_2**: Does the machine you run on have sufficient resources to run these processes in parallell?  
> **username_0**: Yes Pallie, I have Intel i8 7th generation, with 16GB of RAM  
> **username_2**: If your processes request a large amount of RAM/processors per process, that still could be the reason you're not getting parallellised processes  

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## 0 answers

