Foreach-Object -Parallel

Question

I want to run a Foreach-Object in parallel with the invoke-command passed having a scriptblock that references a function.

$Workload += Query-SqlData -SqlServer $SqlServer  -Database master -Query $Tsql | Select Instance, Database
$Workload | ForEach-Object -Parallel {
    $ComputerName  = $($_.Instance).Split('\')[0]
    $SqlServer = $($_.Instance)
    $Database = $($_.Database)
    Invoke-Command -ComputerName $ComputerName -AsJob -JobName $Database -ScriptBlock ${Function:Start-UpdateStatistics} `
    -ArgumentList $SqlServer ,$Database
}

But it fails with:
Cannot validate argument on parameter 'ScriptBlock'. The argument is null

When I run the Invoke-Command directly, it runs as expected.

    Invoke-Command -ComputerName $ComputerName -AsJob -JobName $Database -ScriptBlock ${Function:Start-UpdateStatistics} `
    -ArgumentList $SqlServer ,$Database

How can i get this to work in a Foreach-Object parallel ?

Answer 1

You're running a runspace inside a runspace. You would need the using: scope to access a variable inside the foreach script block.

$a = 1
foreach-object -parallel { $using:a }

But invoke-command with multiple computers is already running in parallel, so you don't need the foreach -parallel.

invoke-command computer1,computer2,computer3 { sleep 10; "$env:computername done" }