Parallelism

Can I use PowerShell 7 “-Parallel” option against SharePoint list items with PnP.PowerShell? Can I run something like:

$items | ForEach-Object -Parallel {
    $listItem = Set-PnPListItem -List "LargeList" -Identity $_ -Values @{"Number" = $(Get-Random -Minimum 100 -Maximum 200 ) }
} 

Yes, sure… But! Since it’s a cloud operation against Microsoft 365 – you will be throttled if you start more than 2 parallel threads! Using just 2 threads does not provide significant performance improvements.

Batching

So, try PnP.PowerShell batches instead. When you use batching, number of requests to the server are much lower. Consider something like:

$batch = New-PnPBatch
1..100 | ForEach-Object{ Add-PnPListItem -List "ItemTest" -Values @{"Title"="Test Item Batched $_"} -Batch $batch }
Invoke-PnPBatch -Batch $batch

Measurements

Adding and setting 100 items with “Add-PnPListItem” and “Set-PnPListItem” in a large (more than 5000 items ) SharePoint list measurements:

	Add-PnPListItem Time per item, seconds	Set-PnPListItem Time per item, seconds
Regular, without batching	1.26	1.55
Using batches (New-PnPBatch)	0.10	0.80
Using “Parallel” option, with ThrottleLimit 2	0.69	0.79
Using “Parallel” option, with ThrottleLimit 3	0.44 (fails level: ~4/100)	0.53 (fails level: ~3/100)

Adding items with PnP.PowerShell batching is much faster than without batching.

More:

• Batching in PnP PowerShell | PnP PowerShell
• PnP PowerShell
• PowerShell ForEach-Object Parallel Feature
• Avoid getting throttled or blocked in SharePoint Online