Here I’m trying to figure out – how much PowerShell Parallel option is beneficial and how to avoid throttling…
Let us test, how long would it take to create a SharePoint site, if we use regular (sequential) loop or parallelism (I’m creation a sample set of 50 SharePoint Sites in a row):
Regular (Sequential) seconds per site
Parallel, 100 sites in batch seconds per site
Parallel, 500 sites in batch seconds per site
Regular (Sequential)
3.0
Parallel, ThrottleLimit = 2
1.60
0.91
Parallel, ThrottleLimit = 5
0.69
Parallel, ThrottleLimit = 10
0.2 – 0.3
Parallel, ThrottleLimit = 20
0.17
Interesting, but I did not get even one (throttling or any other) error during creation 500 sites.
Get sites details
Now let us test, how long it takes to get sites details with Get-PnPTenantSite (I use a sample set of 500 sites):
Test type
Regular (Sequential), seconds per site
Parallel sample = 100 sites, seconds per site
Parallel sample = 200 sites, seconds per site
Parallel sample = 500 sites, seconds per site
Regular (Sequential)
0.65
Parallel, ThrottleLimit = 2
0.40
0.33
0.31
Parallel, ThrottleLimit = 5
0.17
0.14
0.36 (errors)
Parallel, ThrottleLimit = 10
0.11 (errors)
0.11 (errors)
0.34 (errors)
Parallel, ThrottleLimit = 20
0.12 errors+
0.07 errors+
0.52 (errors)
(errors) means there were small number of errors during test… e.g.
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:
Scenario: You have a large (>5k items) list in SharePoint Online you need to clean-up, for instance:
You need to delete the entire list
You need to delete all the list items, but keep the list
You need to delete some of list items, but keep the others
Deleting a large SharePoint Online list
There was a problem in SharePoint Online – you could not delete a large list – you had to remove all items first, but removing all items was also a challenge. Microsoft improved SharePoint Online, so now it takes ~1 second to delete any SharePoint list, including 5000+ items list via GUI or PowerShell:
Remove-PnPList -Identity $list
command works very fast – ~1 second to delete entire list with >5000 items.
Delete all items in a large SharePoint Online list
In this scenario we need to keep the list, but make it empty (clean it up).
GUI: You can change the list view settings “Item Limit” to <5000 and try to delete items in chunks, but (at least in my experience) when you try to select, let say, 1000 items and delete them via GUI – it says “775 items were not deleted from large list”:
so this option seems like not a good one.
ShareGate: 3-rd party tools like Sharegate, SysKit give a good results too.
for me both methods gave same good result: ~17 items per second ( ~7 times faster than regular).
Deleting some items from a large SPO list
Consider the following scenario: in a large SharePoint list there are items you need to delete and the rest items must stay (typical case might be to purge old items – e.g. items created last year).
In this case you’d
get all list items (or use query to get some list items)
select items that need to be deleted based on your criteria, e.g. created date or last modified date etc.
use PnP.PowerShell batches to delete only what you need
# to get all list items
$listItems = Get-PnPListItem -List Tasks -PageSize 1000
# or to get some list items
$listItems = Get-PnPListItem -List Tasks -Query <query>
# select items to delete
$itemsToDelete = $listItems | ?{$_.Modified -lt $threshold}
# delete some list items
$batch = New-PnPBatch
$itemsToDelete | Foreach-Object { Remove-PnPListItem -List $list -Identity $_ -Batch $batch }
Invoke-PnPBatch -Batch $batch
PnP.PowerShell batch vs ScriptBlock
How fast are PnP batches? What is better in terms of performance – ScriptBlock or Batching? Here are my measurements:
Time elapsed, seconds
with batches
with scriptBlock
without batches
Add-PnPListItem (100 items)
6-10 seconds
60-120 seconds
Add-PnPListItem (500 items)
20-40 seconds
230-600 seconds
Add-PnPListItem (7000 items)
314-600 seconds
Add-PnPListItem (37000 items)
3200 seconds
Remove-PnPListItem (1000 items)
58-103 seconds
58 seconds
430-1060 seconds
Remove-PnPListItem (7000 items)
395-990 seconds 3000 seconds
397-980 seconds
Remove-PnPListItem (30000 items)
one big batch : 13600 seconds 30 batches 1000 items each: 3500 seconds
both – PnP PowerShell batches and ScriptBlocks are 7-10 times faster than plain PnP PowerShell!
Can we use Microsoft Graph API to complete the same task? TBC…
Note… For the sake of history: It used to be like that for 5k+ lists: “Remove-PnPList” fails with a message “The attempted operation is prohibited because it exceeds the list view threshold enforced by the administrator”. Deleting with GUI failed too.