The function will query the SharePoint web applications or the Site Collection for all the workflows and the result codes. It's useful to have overview about all running workflows due to build-in limits.

Get-SPWorkflowExecutionStatus

Function mms-SPRunningWorkflows {
    <#
    .Synopsis
    List of running workflows for the site
    
    .Description
    Due to running worfklows you can face to various .Net compilation errors. The most know are:
        - Could not write to output file ... The Directory is invalid
        - The workflow can not run and will be saved only
        - etc.
    As the workflows are laoded in the memory you can see the increased memory consumption again the baseline. It is due to fact
    of the limits by SharePoint itself, for example:
        - workflow associations per list: 100
        - Published Workflow definition per web site: 1000
        - Total associated Workflows for web site: 1799
        - etc.

    .INPUTS
    -URL <> 
    parameter converted to get spsite variable. If empty, all sites will be queried.

    .OUTPUTS
    The default output is a new object, contans basic info about of all running workflows on the site (all except "completed", "Null", "Cancelled").
    The possible workflow statuses are:
        None = 0,
        Locked = 1,
        Running = 2,
        Completed = 4,
        Cancelled = 8,
        Expiring = 16,
        Expired = 32,
        Faulting = 64,
        Terminated = 128,
        Suspended = 256,
        Orphaned = 512,
        HasNewEvents = 1024,
        NotStarted = 2048,
        All = 4098
    
    .Example
    List of all executed workflows
    
    PS C:\>mms-SPRunningWorkflows |ft -a

    Web                                   List              Item                                                                      State Created             Modified           
    ---                                   ----              ----                                                                      ----- -------             --------           
    http://sptest/SC                      Offers            1514002311                                                            Completed 17.12.2014 8:47:42  17.12.2014 8:47:42 
    http://sptest/SC                      Offers            1514002312                                                            Completed 17.12.2014 8:48:14  17.12.2014 8:48:14 
    http://sptest/SC                      Offers            1514002313                                                            Completed 17.12.2014 8:49:00  17.12.2014 8:49:00 
    http://sptest/SC                      Offers            1514002313                                                            Completed 17.12.2014 8:49:00  17.12.2014 8:49:00 
    http://sptest/SC                      Offers            1514002314                                                            Completed 17.12.2014 8:49:25  17.12.2014 8:49:25 
    http://sptest/SC                      Offers            1514002479                                                            Completed 17.12.2014 13:18:12 17.12.2014 13:18:12

    .Example
    Count executed workflows on the site collection, based on the status

    PS C:\>mms-SPRunningWorkflows -URL http://sptest/sc |group state |sort -Descending |ft Count, Name -AutoSize

    Count Name                           
    ----- ----                           
      586 Completed                      
       17 Running                        
        4 Cancelled, Faulting, Terminated

    .Example
    Count runing workflows on te sharepoint, group by URL

    PS C:\>mms-SPRunningWorkflows | ?{$_.state -eq "Running"} | group web | sort -Descending |ft Count, Name -AutoSize

    Count Name                                 
    ----- ----                                 
      868 http://sp/sc        
       17 http://sptest/sc


    .Notes
    Last Updated: February 9, 2015
    Version     : 1.0

    .Link
    https://technet.microsoft.com/en-us/library/cc262787.aspx#Workflow
    #>



    Param(
        [Parameter(Position=0, ValueFromPipeline=$true, ValueFromPipelineByPropertyName, ParameterSetName="URL")]
        [String[]]$URL = $null
    )

    Add-PSSnapin Microsoft.SharePoint.PowerShell -erroraction SilentlyContinue
    
    if (!$URL) {$webs = get-spsite -limit all |Get-SPWeb -limit All}
    else {$webs = foreach ($link in $URL){get-spsite $link | get-spweb}}

    foreach($Web in $webs){
        foreach ($splist in $web.Lists) {
            $assoc = $spList.WorkflowAssociations | where {$_.RunningInstances -gt 0} 
            if($assoc -ne $null) {
                foreach($item in $spList.Items){
                    $item.workflows | %{
                            [PSCustomObject] @{ 
                                Web = $Web.Url
                                List = $spList.Title
                                Item = $item.Title
                                State = $_.InternalState
                                Created = $_.created
                                Modified = $_.modified
                            }
                            <#      # If you would lke to cancel the workflows, uncomment this block. Be sure you are running with elevated permission (farm account)
                                    $web.AllowUnsafeUpdates = true
                                    [Microsoft.SharePoint.Workflow.SPWorkflowManager]::CancelWorkflow($item.workflows)
                                    $web.AllowUnsafeUpdates = false
                            #>
                    }
                }
            }
        }
    }
}