PowerShell - fast remove a directory with 10,000+ files

Question

I am sick of File Explorer's super slow deletion speed, so I tried to write a PowerShell script to make deletion faster, and while it does its job, its speed isn't as high as what I intended it to be.

I have written this:

Function Fast-Delete {
    Param(
    [Parameter(Valuefrompipeline=$True, Mandatory=$True)] [String]$Directory0
    )
    Write-Warning "This Process Will Delete Everything In The Target Directory: $Directory0, Do You Want To Confirm Deletion?" -Warningaction Inquire
    $Directory=$Directory0
    While ((Get-Childitem -Path $Directory0 -Depth 0 -Force).Count -Ne 0) {
    If ((Get-Childitem -Path $Directory -Directory -Force -Depth 0).Count -Ne 0) {
    $Directory=(Get-Childitem -Path $Directory -Directory -Force -Depth 0).Fullname | Select-Object -Index 0
    }
    If ((Get-Childitem -Path $Directory -File -Force).Count -Ne 0) {
    (Get-Childitem -Path $Directory -File -Recurse -Force).Fullname | Foreach {Remove-Item -Path $_}
    }
    $Directory1=$Directory
    $Directory=$Directory | Split-Path -Parent
    Remove-Item -Path $Directory1
    }
    Remove-Item -Path $Directory0
}

It is significantly faster than explorer, but still isn't ideal, I have tested it, I used it to delete 208,000 files in 1,000 folders , and the folders disappear at speed of 1 per second, so it's about 208 files/s, now the next challenge should be parallelization, But this is currently really way above me, but it shouldn't be too hard, I am just not experienced enough.

Update2

I have managed to make it run in parallel with this script:

function Parallel-Delete {
    param(
    [Parameter(Valuefrompipeline=$true, Mandatory=$true, Position=0)] [array]$filelist,
    [Parameter(Valuefrompipeline=$true, Mandatory=$true, Position=1)] [int]$number
    )
    0..($filelist.count-1) | Where-Object {$_ % 16 -eq $number} | foreach {Remove-Item -Path $filelist[$_]}
}

Function Fast-Delete {
    Param(
    [Parameter(Valuefrompipeline=$True, Mandatory=$True)] [String]$Directory0
    )
    Write-Warning "This Process Will Delete Everything In The Target Directory:  $Directory0, Do You Want To Confirm Deletion?" -Warningaction Inquire
    $Directory=$Directory0
    While ((Get-Childitem -Path $Directory0 -Depth 0 -Force).Count -Ne 0) {
        If ((Get-Childitem -Path $Directory -Directory -Force -Depth 0).Count -Ne 0) {
            $Directory=(Get-Childitem -Path $Directory -Directory -Force -Depth 0).Fullname | Select-Object -Index 0
        }
        If ((Get-Childitem -Path $Directory -File -Force).Count -Ne 0) {
            If ((Get-Childitem -Path $Directory -File -Force).Count -Ge 128) {
                [array]$filelist=(Get-Childitem -Path $Directory -File -Force).Fullname
                0..15 | foreach-object {Invoke-Command -ScriptBlock { Parallel-Delete $filelist $_}}
                } else {
                (Get-Childitem -Path $Directory -File -Force).Fullname | Foreach {Remove-Item -Path $_}
            }
        }
        $Directory1=$Directory
        $Directory=$Directory | Split-Path -Parent
        Remove-Item -Path $Directory1
        }
    Remove-Item -Path $Directory0 -erroraction silentlycontinue
}
$Directory0=Read-Host "Please input target directory to be deleted"
Fast-Delete $Directory0

But it still isn't ideal, it isn't 15 times faster as expected, what did I miss?

Edit: simplified the creation of parallel processes.

Answer 1

As pointed out in a comment from @Lee_Daily, reinventing the wheel from an interpreted language like PowerShell will be slower than a native implementation. If your primary concern is speed, use the correct tool for the job. We have a native implementation in robocopy.

It has an option /mir

Mirrors a directory tree (equivalent to /e plus /purge). Using this option with the /e option and a destination directory, overwrites the destination directory security settings.

Below is the robocopy purge method using your framework:

Param(
    [Parameter(Valuefrompipeline=$True, Mandatory=$True)] [String]$Directory
)

Function Fast-Delete {
    Param(
        [Parameter(Valuefrompipeline=$True, Mandatory=$True)] [String]$Directory
    )

    Write-Warning "This Process Will Delete Everything In The Target Directory:  $Directory, Do You Want To Confirm Deletion?" -Warningaction Inquire

    $emptyDir = GetRandomTempPath
    mkdir $emptyDir

    robocopy $emptyDir $Directory /mir

    Remove-Item -Path $Directory -erroraction silentlycontinue
    Remove-Item -Path $emptyDir -erroraction silentlycontinue
}

Function GetRandomTempPath {
    Do {
        $fullPath = Join-Path -Path $env:TEMP -ChildPath [System.IO.Path]::GetRandomFileName()
    } While (Test-Path $fullPath);

    Return $fullPath;
} 

Fast-Delete $Directory

Save as: Fast-Delete.ps1

Comparison of delete methods (2 GB, 10,000 files in directory):

• remove-item: 2.4 files/sec average (n=10)
• /purge : 2.4 files/sec average (n=3)
• /purge /mt: 2.5 files/sec average (n=3)
• explorer-based click-delete: 3.1 files/sec (n=30)
• /mir: 5.5 files/sec (n = 100)

Answer 2

The foreach-object is not run in parallel by default. You need specify the -Parallel parameter. And the version of Powershell need be greater than 7.0

See Official Blob and Official document