PowerShell to delete SharePoint list items in batch mode.

DeleteListItems.ps1

function DeleteListItems{
   <#
   .SYNOPSIS
      Deletes SharePoint List Items in batch
      
   .DESCRIPTION
      Deleted SharePoint List items in batch and provide sleep between batch. By default, it will delete all List Items.
      You can delete List Items based on the CAML Query input parameter.
      
   .PARAMETER ListUrl
      Mandatory. SharePoint List Url to be deleted. For example: http://www.contoso.com/Lists/CustomList
      
   .PARAMETER BatchSize
      Optional. Batch Size per deletion request. For example if you specify 2000, and your list contains 10.000 items, then the 
      application will execute 5 deletion request with 2000 items deletion per request. Default: 2000
   
   .PARAMETER CamlQuery
      Optional. Valid CAML Query to specify deletion criteria. Default: "<Where><Geq><FieldRef Name='ID' /><Value Type='Counter'>1</Value></Geq></Where>"
   
   .INPUTS
      Parameters above
   
   .OUTPUTS
      None
   
   .NOTES
      Version: 1.1
      Author: Riwut Libinuko
      Creation Date: 29/12/2015
      Last Update: 11/03/2018
      
   .EXAMPLE
      DeleteListItems -ListUrl http://www.contoso.com/Lists/ListToDelete
   
   #>
   Param (
      [Parameter(Mandatory=$true)][string]$listUrl,
      [int]$batchSize=2000,
      [string]$camlQuery = "<Where><Geq><FieldRef Name='ID' /><Value Type='Counter'>1</Value></Geq></Where>" 
   )

   $spSite = new-object Microsoft.SharePoint.SPSite($listUrl)
   $spWeb = $spSite.OpenWeb()
   $list = $spWeb.GetList($listUrl)

   Write-host "Intializing SharePoint object for $listUrl"
   $starttime=get-date
   Write-host "Deleting items in $listUrl with in $batchSize per batch"

   $query = New-Object Microsoft.SharePoint.SPQuery
   $query.ViewAttributes = "Scope='Recursive'"
   $query.RowLimit = $batchSize
   $query.Query = $camlQuery

    $itemCount = 0
    $listId = $list.ID
    $command = [System.String]::Format( "<Method><SetList>{0}</SetList><SetVar Name=`"ID`">{1}</SetVar><SetVar Name=`"Cmd`">Delete</SetVar></Method>", $listId, "{0}" )

    do
    {
        [System.Text.StringBuilder]$batchXml = New-Object "System.Text.StringBuilder"
        $batchXml.Append("<?xml version=`"1.0`" encoding=`"UTF-8`"?><Batch>")

        $listItems = $list.GetItems($query)
        $listItems.ListItemCollectionPosition
        $query.ListItemCollectionPosition = $listItems.ListItemCollectionPosition
        Write-Host "Preparing" -NoNewline
        if($listItems.Count -gt 0) {
            foreach ($item in $listItems)
            {
                if($item -ne $null){
                    $batchXml.Append([System.String]::Format($command, $item.ID.ToString())) | Out-Null;
                    $itemCount++;
                    Write-Host "." -NoNewline
                }            
            }
        
            Write-Host "."
            $batchXml.Append("</Batch>")
            Write-Host "Total $($listItems.Count) will be deleted.." 
            Write-host "Sending batch command"
            $web.ProcessBatchData($batchXml.ToString()) | Out-Null  
            Start-Sleep -Seconds 2 #Need to give some fresh air
        }
    }
    while ($query.ListItemCollectionPosition -ne $null)

   $endtime=get-date
   $span=[System.timespan]($endtime - $starttime)
   $timeSpent=$span.TotalSeconds

   Write-host "Deleting total $itemCount item(s) in $timeSpent seconds"
   $spWeb.Dispose()
   $spSite.Dispose()
}