functions/Get-DbaLastGoodCheckDb.ps1

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function Get-DbaLastGoodCheckDb {
    <#
.SYNOPSIS
Get date/time for last known good DBCC CHECKDB
 
.DESCRIPTION
Retrieves and compares the date/time for the last known good DBCC CHECKDB, as well as the creation date/time for the database.
 
This function supports SQL Server 2005+
 
Please note that this script uses the DBCC DBINFO() WITH TABLERESULTS. DBCC DBINFO has several known weak points, such as:
 - DBCC DBINFO is an undocumented feature/command.
 - The LastKnowGood timestamp is updated when a DBCC CHECKFILEGROUP is performed.
 - The LastKnowGood timestamp is updated when a DBCC CHECKDB WITH PHYSICAL_ONLY is performed.
 - The LastKnowGood timestamp does not get updated when a database in READ_ONLY.
 
An empty ($null) LastGoodCheckDb result indicates that a good DBCC CHECKDB has never been performed.
 
SQL Server 2008R2 has a "bug" that causes each databases to possess two dbi_dbccLastKnownGood fields, instead of the normal one.
This script will only display this function to only display the newest timestamp. If -Verbose is specified, the function will announce every time more than one dbi_dbccLastKnownGood fields is encountered.
 
.PARAMETER SqlInstance
The SQL Server that you're connecting to.
 
.PARAMETER SqlCredential
Credential object used to connect to the SQL Server as a different user
 
.PARAMETER Database
The database(s) to process - this list is auto-populated from the server. If unspecified, all databases will be processed.
 
.PARAMETER ExcludeDatabase
The database(s) to exclude - this list is auto-populated from the server
 
.PARAMETER Silent
Use this switch to disable any kind of verbose messages
 
.NOTES
Tags: CHECKDB, Database
Author: Jakob Bindslet (jakob@bindslet.dk)
 
Website: https://dbatools.io
Copyright: (C) Chrissy LeMaire, clemaire@gmail.com
License: GNU GPL v3 https://opensource.org/licenses/GPL-3.0
 
.LINK
DBCC CHECKDB:
 https://msdn.microsoft.com/en-us/library/ms176064.aspx
 http://www.sqlcopilot.com/dbcc-checkdb.html
Data Purity:
 http://www.sqlskills.com/blogs/paul/checkdb-from-every-angle-how-to-tell-if-data-purity-checks-will-be-run/
 https://www.mssqltips.com/sqlservertip/1988/ensure-sql-server-data-purity-checks-are-performed/
 
.EXAMPLE
Get-DbaLastGoodCheckDb -SqlInstance ServerA\sql987
 
Returns a custom object displaying Server, Database, DatabaseCreated, LastGoodCheckDb, DaysSinceDbCreated, DaysSinceLastGoodCheckDb, Status and DataPurityEnabled
 
.EXAMPLE
Get-DbaLastGoodCheckDb -SqlInstance ServerA\sql987 -SqlCredential (Get-Credential sqladmin) | Format-Table -AutoSize
 
Returns a formatted table displaying Server, Database, DatabaseCreated, LastGoodCheckDb, DaysSinceDbCreated, DaysSinceLastGoodCheckDb, Status and DataPurityEnabled.
Authenticates with SQL Server using alternative credentials.
 
#>

    [CmdletBinding()]
    param (
        [parameter(Mandatory = $true, ValueFromPipeline = $true)]
        [Alias("ServerInstance", "SqlServer")]
        [DbaInstanceParameter[]]$SqlInstance,
        [Alias("Credential")]
        [PSCredential]
        $SqlCredential,
        [Alias("Databases")]
        [object[]]$Database,
        [object[]]$ExcludeDatabase,
        [switch]$Silent
    )
    process {
        foreach ($instance in $SqlInstance) {
            try {
                Write-Message -Level Verbose -Message "Connecting to $instance"
                $server = Connect-SqlInstance -SqlInstance $instance -SqlCredential $sqlcredential
            }
            catch {
                Stop-Function -Message "Failure" -Category ConnectionError -ErrorRecord $_ -Target $instance -Continue
            }

            if ($server.versionMajor -lt 9) {
                Stop-Function -Message "Get-DbaLastGoodCheckDb is only supported on SQL Server 2005 and above. Skipping Instance." -Continue -Target $instance
            }

            $dbs = $server.Databases

            if ($Database) {
                $dbs = $dbs | Where-Object Name -In $Database
            }

            if ($ExcludeDatabase) {
                $dbs = $dbs | Where-Object Name -NotIn $ExcludeDatabase
            }

            foreach ($db in $dbs) {
                Write-Message -Level Verbose -Message "Processing $db on $instances"

                if ($db.IsAccessible -eq $false) {
                    Stop-Function -Message "The database $db is not accessible. Skipping database." -Continue -Target $db
                }

                $sql = "DBCC DBINFO ([$($db.name)]) WITH TABLERESULTS"
                Write-Message -Level Debug -Message "T-SQL: $sql"

                $resultTable = $db.ExecuteWithResults($sql).Tables[0]
                [datetime[]]$lastKnownGoodArray = $resultTable | Where-Object Field -eq 'dbi_dbccLastKnownGood' | Select-Object -ExpandProperty Value

                ## look for databases with two or more occurrences of the field dbi_dbccLastKnownGood
                if ($lastKnownGoodArray.count -ge 2) {
                    Write-Message -Level Verbose -Message "The database $db has $($lastKnownGoodArray.count) dbi_dbccLastKnownGood fields. This script will only use the newest!"
                }
                [datetime]$lastKnownGood = $lastKnownGoodArray | Sort-Object -Descending | Select-Object -First 1

                [int]$createVersion = ($resultTable | Where-Object Field -eq 'dbi_createVersion').Value
                [int]$dbccFlags = ($resultTable | Where-Object Field -eq 'dbi_dbccFlags').Value

                if (($createVersion -lt 611) -and ($dbccFlags -eq 0)) {
                    $dataPurityEnabled = $false
                }
                else {
                    $dataPurityEnabled = $true
                }

                $daysSinceCheckDb = (New-TimeSpan -Start $lastKnownGood -End (Get-Date)).Days
                $daysSinceDbCreated = (New-TimeSpan -Start $db.createDate -End (Get-Date)).Days

                if ($daysSinceCheckDb -lt 7) {
                    $Status = 'Ok'
                }
                elseif ($daysSinceDbCreated -lt 7) {
                    $Status = 'New database, not checked yet'
                }
                else {
                    $Status = 'CheckDB should be performed'
                }

                if ($lastKnownGood -eq '1/1/1900 12:00:00 AM') { Remove-Variable -Name lastKnownGood, daysSinceCheckDb }

                [PSCustomObject]@{
                    ComputerName             = $server.NetName
                    InstanceName             = $server.ServiceName
                    SqlInstance              = $server.DomainInstanceName
                    Database                 = $db.name
                    DatabaseCreated          = $db.createDate
                    LastGoodCheckDb          = $lastKnownGood
                    DaysSinceDbCreated       = $daysSinceDbCreated
                    DaysSinceLastGoodCheckDb = $daysSinceCheckDb
                    Status                   = $status
                    DataPurityEnabled        = $dataPurityEnabled
                    CreateVersion            = $createVersion
                    DbccFlags                = $dbccFlags
                }
            }
        }
    }
}