functions/Measure-DbaDbVirtualLogFile.ps1
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function Measure-DbaDbVirtualLogFile { <# .SYNOPSIS Returns calculations on the database virtual log files for database on a SQL instance. .DESCRIPTION Having a transaction log file with too many virtual log files (VLFs) can hurt database performance. Too many VLFs can cause transaction log backups to slow down and can also slow down database recovery and, in extreme cases, even affect insert/update/delete performance. References: http://www.sqlskills.com/blogs/kimberly/transaction-log-vlfs-too-many-or-too-few/ http://blogs.msdn.com/b/saponsqlserver/archive/2012/02/22/too-many-virtual-log-files-vlfs-can-cause-slow-database-recovery.aspx If you've got a high number of VLFs, you can use Expand-SqlTLogResponsibly to reduce the number. .PARAMETER SqlInstance The target SQL Server instance or instances. .PARAMETER SqlCredential Login to the target instance using alternative credentials. Accepts PowerShell credentials (Get-Credential). Windows Authentication, SQL Server Authentication, Active Directory - Password, and Active Directory - Integrated are all supported. For MFA support, please use Connect-DbaInstance. .PARAMETER Database Specifies the database(s) to process. Options for this list are auto-populated from the server. If unspecified, all databases will be processed. .PARAMETER ExcludeDatabase Specifies the database(s) to exclude from processing. Options for this list are auto-populated from the server. .PARAMETER IncludeSystemDBs If this switch is enabled, system database information will be displayed. .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: VLF, Database 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/Measure-DbaDbVirtualLogFile .EXAMPLE PS C:\> Measure-DbaDbVirtualLogFile -SqlInstance sqlcluster Returns all user database virtual log file counts for the sqlcluster instance. .EXAMPLE PS C:\> Measure-DbaDbVirtualLogFile -SqlInstance sqlserver | Where-Object {$_.Count -ge 50} Returns user databases that have 50 or more VLFs. .EXAMPLE PS C:\> @('sqlserver','sqlcluster') | Measure-DbaDbVirtualLogFile Returns all VLF information for the sqlserver and sqlcluster SQL Server instances. Processes data via the pipeline. .EXAMPLE PS C:\> Measure-DbaDbVirtualLogFile -SqlInstance sqlcluster -Database db1, db2 Returns VLF counts for the db1 and db2 databases on sqlcluster. #> [CmdletBinding()] [OutputType([System.Collections.ArrayList])] param ([parameter(ValueFromPipeline, Mandatory)] [DbaInstanceParameter[]]$SqlInstance, [PSCredential]$SqlCredential, [object[]]$Database, [object[]]$ExcludeDatabase, [switch]$IncludeSystemDBs, [switch]$EnableException ) process { foreach ($instance in $SqlInstance) { try { $server = Connect-SqlInstance -SqlInstance $instance -SqlCredential $sqlcredential } catch { Stop-Function -Message "Error occurred while establishing connection to $instance" -Category ConnectionError -ErrorRecord $_ -Target $instance -Continue } $dbs = $server.Databases if ($Database) { $dbs = $dbs | Where-Object Name -in $Database } if ($ExcludeDatabase) { $dbs = $dbs | Where-Object Name -NotIn $ExcludeDatabase } if (!$IncludeSystemDBs) { $dbs = $dbs | Where-Object IsSystemObject -eq $false } foreach ($db in $dbs) { try { $data = Get-DbaDbVirtualLogFile -SqlInstance $server -Database $db.Name $logFile = Get-DbaDbFile -SqlInstance $server -Database $db.Name | Where-Object Type -eq 1 $active = $data | Where-Object Status -eq 2 $inactive = $data | Where-Object Status -eq 0 [PSCustomObject]@{ ComputerName = $server.ComputerName InstanceName = $server.ServiceName SqlInstance = $server.DomainInstanceName Database = $db.name Total = $data.Count TotalCount = $data.Count Inactive = if ($inactive -and $null -eq $inactive.Count) { 1 } else { $inactive.Count } Active = if ($active -and $null -eq $active.Count) { 1 } else { $active.Count } LogFileName = $logFile.LogicalName -join "," LogFileGrowth = $logFile.Growth -join "," LogFileGrowthType = $logFile.GrowthType -join "," } | Select-DefaultView -Property ComputerName, InstanceName, SqlInstance, Database, Total } catch { Stop-Function -Message "Unable to query $($db.name) on $instance." -ErrorRecord $_ -Target $db -Continue } } } } } |