functions/Test-DbaMaxDop.ps1
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function Test-DbaMaxDop { <# .SYNOPSIS Displays information relating to SQL Server Max Degree of Parallelism setting. Works on SQL Server 2005-2016. .DESCRIPTION Inspired by Sakthivel Chidambaram's post about SQL Server MAXDOP Calculator (https://blogs.msdn.microsoft.com/sqlsakthi/p/maxdop-calculator-SqlInstance/), this script displays a SQL Server's: max dop configured, and the calculated recommendation. For SQL Server 2016 shows: - Instance max dop configured and the calculated recommendation - max dop configured per database (new feature) More info: https://support.microsoft.com/en-us/kb/2806535 https://blogs.msdn.microsoft.com/sqlsakthi/2012/05/23/wow-we-have-maxdop-calculator-for-sql-server-it-makes-my-job-easier/ These are just general recommendations for SQL Server and are a good starting point for setting the "max degree of parallelism" option. .PARAMETER SqlInstance The SQL Server instance(s) to connect to. .PARAMETER SqlCredential Login to the target instance using alternative credentials. Windows and SQL Authentication supported. Accepts credential objects (Get-Credential) .PARAMETER Detailed Output all properties, will be deprecated in 1.0.0 release. .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: MaxDop, SpConfigure Author : Claudio Silva (@claudioessilva) Requires: sysadmin access on SQL Servers dbatools PowerShell module (https://dbatools.io, clemaire@gmail.com) Copyright (c) 2018 by dbatools, licensed under MIT License: MIT https://opensource.org/licenses/MIT .LINK https://dbatools.io/Test-DbaMaxDop .EXAMPLE Test-DbaMaxDop -SqlInstance sql2008, sqlserver2012 Get Max DOP setting for servers sql2008 and sqlserver2012 and also the recommended one. .EXAMPLE Test-DbaMaxDop -SqlInstance sql2014 | Select-Object * Shows Max DOP setting for server sql2014 with the recommended value. Piping the output to Select-Object * will also show the 'NUMANodes' and 'NumberOfCores' of each instance .EXAMPLE Test-DbaMaxDop -SqlInstance sqlserver2016 | Select-Object * Get Max DOP setting for servers sql2016 with the recommended value. Piping the output to Select-Object * will also show the 'NUMANodes' and 'NumberOfCores' of each instance. Because it is an 2016 instance will be shown 'InstanceVersion', 'Database' and 'DatabaseMaxDop' columns. #> [CmdletBinding()] [OutputType([System.Collections.ArrayList])] param ( [parameter(Position = 0, Mandatory, ValueFromPipeline)] [Alias("ServerInstance", "SqlServer", "SqlServers")] [DbaInstance[]]$SqlInstance, [PSCredential]$SqlCredential, [switch]$Detailed, [Alias('Silent')] [switch]$EnableException ) begin { Test-DbaDeprecation -DeprecatedOn 1.0.0 -Parameter Detailed $notesDopLT = "Before changing MaxDop, consider that the lower value may have been intentionally set." $notesDopGT = "Before changing MaxDop, consider that the higher value may have been intentionally set." $notesDopZero = "This is the default setting. Consider using the recommended value instead." $notesDopOne = "Some applications like SharePoint, Dynamics NAV, SAP, BizTalk has the need to use MAXDOP = 1. Please confirm that your instance is not supporting one of these applications prior to changing the MaxDop." $notesAsRecommended = "Configuration is as recommended." } process { $hasScopedConfig = $false foreach ($instance in $SqlInstance) { try { Write-Message -Level Verbose -Message "Connecting to $instance" $server = Connect-SqlInstance -SqlInstance $instance -SqlCredential $SqlCredential -MinimumVersion 9 } catch { Stop-Function -Message "Failure" -Category ConnectionError -ErrorRecord $_ -Target $instance -Continue } #Get current configured value $maxDop = $server.Configuration.MaxDegreeOfParallelism.ConfigValue try { #represents the Number of NUMA nodes $sql = "SELECT COUNT(DISTINCT memory_node_id) AS NUMA_Nodes FROM sys.dm_os_memory_clerks WHERE memory_node_id!=64" $numaNodes = $server.ConnectionContext.ExecuteScalar($sql) } catch { Stop-Function -Message "Failed to get Numa node count." -ErrorRecord $_ -Target $server -Continue } try { #represents the Number of Processor Cores $sql = "SELECT COUNT(scheduler_id) FROM sys.dm_os_schedulers WHERE status = 'VISIBLE ONLINE'" $numberOfCores = $server.ConnectionContext.ExecuteScalar($sql) } catch { Stop-Function -Message "Failed to get number of cores." -ErrorRecord $_ -Target $server -Continue } #Calculate Recommended Max Dop to instance #Server with single NUMA node if ($numaNodes -eq 1) { if ($numberOfCores -lt 8) { #Less than 8 logical processors - Keep MAXDOP at or below # of logical processors $recommendedMaxDop = $numberOfCores } else { #Equal or greater than 8 logical processors - Keep MAXDOP at 8 $recommendedMaxDop = 8 } } else { #Server with multiple NUMA nodes if (($numberOfCores / $numaNodes) -lt 8) { # Less than 8 logical processors per NUMA node - Keep MAXDOP at or below # of logical processors per NUMA node $recommendedMaxDop = [int]($numberOfCores / $numaNodes) } else { # Greater than 8 logical processors per NUMA node - Keep MAXDOP at 8 $recommendedMaxDop = 8 } } #Setting notes for instance max dop value $notes = $null if ($maxDop -eq 1) { $notes = $notesDopOne } else { if ($maxDop -ne 0 -and $maxDop -lt $recommendedMaxDop) { $notes = $notesDopLT } else { if ($maxDop -ne 0 -and $maxDop -gt $recommendedMaxDop) { $notes = $notesDopGT } else { if ($maxDop -eq 0) { $notes = $notesDopZero } else { $notes = $notesAsRecommended } } } } [pscustomobject]@{ ComputerName = $server.ComputerName InstanceName = $server.ServiceName SqlInstance = $server.DomainInstanceName InstanceVersion = $server.Version Database = "N/A" DatabaseMaxDop = "N/A" CurrentInstanceMaxDop = $maxDop RecommendedMaxDop = $recommendedMaxDop NUMANodes = $numaNodes NumberOfCores = $numberOfCores Notes = $notes } | Select-DefaultView -Property ComputerName, InstanceName, SqlInstance, Database, DatabaseMaxDop, CurrentInstanceMaxDop, RecommendedMaxDop, Notes # On SQL Server 2016 and higher, MaxDop can be set on a per-database level if ($server.VersionMajor -ge 13) { $hasScopedConfig = $true Write-Message -Level Verbose -Message "SQL Server 2016 or higher detected, checking each database's MaxDop." $databases = $server.Databases | where-object {$_.IsSystemObject -eq $false} foreach ($database in $databases) { if ($database.IsAccessible -eq $false) { Write-Message -Level Verbose -Message "Database $database is not accessible." continue } Write-Message -Level Verbose -Message "Checking database '$($database.Name)'." $dbmaxdop = $database.MaxDop [pscustomobject]@{ ComputerName = $server.ComputerName InstanceName = $server.ServiceName SqlInstance = $server.DomainInstanceName InstanceVersion = $server.Version Database = $database.Name DatabaseMaxDop = $dbmaxdop CurrentInstanceMaxDop = $maxDop RecommendedMaxDop = $recommendedMaxDop NUMANodes = $numaNodes NumberOfCores = $numberOfCores Notes = if ($dbmaxdop -eq 0) { "Will use CurrentInstanceMaxDop value" } else { "$notes" } } | Select-DefaultView -Property ComputerName, InstanceName, SqlInstance, Database, DatabaseMaxDop, CurrentInstanceMaxDop, RecommendedMaxDop, Notes } } } } } |