functions/Get-DbaTempdbUsage.ps1

function Get-DbaTempdbUsage {
    <#
        .SYNOPSIS
            Gets Tempdb usage for running queries.
 
        .DESCRIPTION
            This function queries DMVs for running sessions using tempdb and returns results if those sessions have user or internal space allocated or deallocated against them.
 
        .PARAMETER SqlInstance
            The SQL Instance you are querying against.
 
        .PARAMETER SqlCredential
            If you want to use alternative credentials to connect to the server.
 
        .PARAMETER WhatIf
            Shows what would happen if the command were to run. No actions are actually performed.
 
        .PARAMETER Confirm
            Prompts you for confirmation before executing any changing operations within the command.
 
        .PARAMETER EnableException
            By default, when something goes wrong we try to catch it, interpret it and give you a friendly warning message.
            This avoids overwhelming you with "sea of red" exceptions, but is inconvenient because it basically disables advanced scripting.
            Using this switch turns this "nice by default" feature off and enables you to catch exceptions with your own try/catch.
 
        .NOTES
            Tags: Tempdb, Space
            Author: Chrissy LeMaire (@cl), netnerds.net
 
            Website: https://dbatools.io
            Copyright (c) 2018 by dbatools, licensed under MIT
            License: MIT https://opensource.org/licenses/MIT
 
        .LINK
            https://dbatools.io/Get-DbaTempdbUsage
 
        .EXAMPLE
            PS C:\> Get-DbaTempdbUsage -SqlInstance localhost\SQLDEV2K14
 
            Gets tempdb usage for localhost\SQLDEV2K14
    #>

    [CmdletBinding()]
    param (
        [parameter(Mandatory, ValueFromPipeline)]
        [Alias("ServerInstance", "SqlServer")]
        [DbaInstanceParameter[]]$SqlInstance,
        [PSCredential]$SqlCredential,
        [Alias('Silent')]
        [switch]$EnableException
    )

    process {
        foreach ($instance in $SqlInstance) {
            try {
                $server = Connect-SqlInstance -SqlInstance $instance -SqlCredential $sqlcredential
            }
            catch {
                Stop-Function -Message "Failure" -Category ConnectionError -ErrorRecord $_ -Target $instance -Continue
            }

            if ($server.VersionMajor -le 9) {
                Stop-Function -Message "This function is only supported in SQL Server 2008 or higher." -Continue
            }

            $sql = "SELECT SERVERPROPERTY('MachineName') AS ComputerName,
        ISNULL(SERVERPROPERTY('InstanceName'), 'MSSQLSERVER') AS InstanceName,
        SERVERPROPERTY('ServerName') AS SqlInstance,
        t.session_id AS Spid,
        r.command AS StatementCommand,
        SUBSTRING( est.[text],
                     (r.statement_start_offset / 2) + 1,
                     ((CASE r.statement_end_offset
                            WHEN-1
                            THEN DATALENGTH(est.[text])
                            ELSE
                            r.statement_end_offset
                       END - r.statement_start_offset
                      ) / 2
                     ) + 1
                 ) AS QueryText,
        QUOTENAME(DB_NAME(r.database_id)) + N'.' + QUOTENAME(OBJECT_SCHEMA_NAME(est.objectid, est.dbid)) + N'.'
        + QUOTENAME(OBJECT_NAME(est.objectid, est.dbid)) AS ProcedureName,
        r.start_time AS StartTime,
        tdb.UserObjectAllocated * 8 AS CurrentUserAllocatedKB,
        (t.user_objects_alloc_page_count + tdb.UserObjectAllocated) * 8 AS TotalUserAllocatedKB,
        tdb.UserObjectDeallocated * 8 AS UserDeallocatedKB,
        (t.user_objects_dealloc_page_count + tdb.UserObjectDeallocated) * 8 AS TotalUserDeallocatedKB,
        tdb.InternalObjectAllocated * 8 AS InternalAllocatedKB,
        (t.internal_objects_alloc_page_count + tdb.InternalObjectAllocated) * 8 AS TotalInternalAllocatedKB,
        tdb.InternalObjectDeallocated * 8 AS InternalDeallocatedKB,
        (t.internal_objects_dealloc_page_count + tdb.InternalObjectDeallocated) * 8 AS TotalInternalDeallocatedKB,
        r.reads AS RequestedReads,
        r.writes AS RequestedWrites,
        r.logical_reads AS RequestedLogicalReads,
        r.cpu_time AS RequestedCPUTime,
        s.is_user_process AS IsUserProcess,
        s.[status] AS [Status],
        DB_NAME(r.database_id) AS [Database],
        s.login_name AS LoginName,
        s.original_login_name AS OriginalLoginName,
        s.nt_domain AS NTDomain,
        s.nt_user_name AS NTUserName,
        s.[host_name] AS HostName,
        s.[program_name] AS ProgramName,
        s.login_time AS LoginTime,
        s.last_request_start_time AS LastRequestedStartTime,
        s.last_request_end_time AS LastRequestedEndTime
FROM sys.dm_db_session_space_usage AS t
INNER JOIN sys.dm_exec_sessions AS s
    ON s.session_id = t.session_id
LEFT JOIN sys.dm_exec_requests AS r
    ON r.session_id = s.session_id
LEFT JOIN
          ( SELECT _tsu.session_id,
                        _tsu.request_id,
                        SUM(_tsu.user_objects_alloc_page_count) AS UserObjectAllocated,
                        SUM(_tsu.user_objects_dealloc_page_count) AS UserObjectDeallocated,
                        SUM(_tsu.internal_objects_alloc_page_count) AS InternalObjectAllocated,
                        SUM(_tsu.internal_objects_dealloc_page_count) AS InternalObjectDeallocated
              FROM tempdb.sys.dm_db_task_space_usage AS _tsu
              GROUP BY _tsu.session_id,
                        _tsu.request_id
          ) AS tdb
    ON tdb.session_id = r.session_id
   AND tdb.request_id = r.request_id
OUTER APPLY sys.dm_exec_sql_text(r.[sql_handle]) AS est
WHERE t.session_id != @@SPID
  AND (tdb.UserObjectAllocated - tdb.UserObjectDeallocated + tdb.InternalObjectAllocated - tdb.InternalObjectDeallocated) != 0
OPTION (RECOMPILE);"


            $server.Query($sql)
        }
    }
}