functions/Enable-DbaTraceFlag.ps1

function Enable-DbaTraceFlag {
    <#
    .SYNOPSIS
        Enable a Global Trace Flag
    .DESCRIPTION
        The function will set one or multiple trace flags on the SQL Server instance(s) listed
     
    .PARAMETER SqlInstance
        Allows you to specify a comma separated list of servers to query.
 
    .PARAMETER SqlCredential
        Allows you to login to servers using SQL Logins as opposed to Windows Auth/Integrated/Trusted. To use:
        $cred = Get-Credential, this pass this $cred to the param.
 
        Windows Authentication will be used if DestinationSqlCredential is not specified. To connect as a different Windows user, run PowerShell as that user.
     
    .PARAMETER TraceFlag
        Trace flag number to enable globally
     
    .PARAMETER Silent
        Use this switch to disable any kind of verbose messages (this is required)
 
    .NOTES
        Tags: TraceFlag
        Author: Garry Bargsley (@gbargsley), http://blog.garrybargsley.com
         
        Website: https://dbatools.io
        Copyright: (C) Chrissy LeMaire, clemaire@gmail.com
        License: GNU GPL v3 https://opensource.org/licenses/GPL-3.0
 
    .LINK
        https://dbatools.io/Enable-DbaTraceFlag
 
    .EXAMPLE
        Enable-DbaTraceFlag -SqlInstance sql2016 -TraceFlag 3226
        Enable the trace flag 32266 on SQL Server instance sql2016
 
    .EXAMPLE
        Enable-DbaTraceFlag -SqlInstance sql2016 -TraceFlag 1117, 1118
        Enable multiple trace flags on SQL Server instance sql2016
#>

    [CmdletBinding()]
    param (
        [parameter(Position = 0, Mandatory = $true, ValueFromPipeline = $True)]
        [Alias("ServerInstance", "SqlServer", "SqlServers")]
        [DbaInstanceParameter[]]$SqlInstance,
        [PSCredential]$SqlCredential,
        [parameter(Mandatory)]
        [int[]]$TraceFlag,
        [switch]$Silent
    )
    
    process {
        foreach ($instance in $SqlInstance) {
            Write-Message -Level Verbose -Message "Attempting to connect to $instance"
            
            try {
                $server = Connect-SqlInstance -SqlInstance $instance -SqlCredential $SqlCredential -MinimumVersion 10
            }
            catch {
                Stop-Function -Message "Failure" -Category ConnectionError -ErrorRecord $_ -Target $instance -Continue
            }
            
            $CurrentRunningTraceFlags = Get-DbaTraceFlag -SqlInstance $server
            
            # We could combine all trace flags but the granularity is worth it
            foreach ($tf in $TraceFlag) {
                If ($CurrentRunningTraceFlags.TraceFlag -contains $tf) {
                    Write-Message -Level Warning -Message "The Trace flag $tf is already running globally."
                    continue
                }
                
                try {
                    $query = "DBCC TRACEON ($tf, -1)"
                    $server.Query($query)
                    $server.Refresh()
                    Get-DbaTraceFlag -SqlInstance $server -TraceFlag $TraceFlag
                }
                catch {
                    Stop-Function -Message "Failure" -ErrorRecord $_ -Target $server -Continue
                }
            }
        }
    }
}