Using Pester with Get-DbaLastGoodCheckDb from dbatools

In my last post I showed Get-DbaLastGoodCheckDb  from dbatools. This module is a community based project written by excellent, brilliant people in their own time and available to you free. To find out more and how to use and install it visit https://dbatools.io

In a similar fashion to my post about using Pester with Test-DBALastBackup I thought I would write some Pester tests for Get-DbaLastGoodCheckDb as well

Pester provides a framework for running unit tests to execute and validate PowerShell commands from within PowerShell. Pester consists of a simple set of functions that expose a testing domain-specific language (DSL) for isolating, running, evaluating and reporting the results of PowerShell commands.

First we will use Test Cases again to quickly test a number of instances and see if any servers have a database which does not have a successful DBCC Checkdb. We will need to use the -Detailed parameter of Get-DbaLastGoddCheckDb so that we can access the status property. I have filled the $SQLServers variable with the names of my SQLServers in my lab that are running and are not my broken SQL2008 box.

The status property will contain one of three statements

  • Ok (This means that a successful test was run in the last 7 days
  • New database, not checked yet
  • CheckDb should be performed

We want to make sure that none of the results from the command have the second two statements. We can do this by adding two checks in the test and if either fails then the test will fail.

 Describe "Testing Last Known Good DBCC" {
$SQLServers = (Get-VM -ComputerName beardnuc | Where-Object {$_.Name -like '*SQL*' -and $_.Name -ne 'SQL2008Ser2008' -and $_.State -eq 'Running'}).Name
$testCases= @()
$SQLServers.ForEach{$testCases += @{Name = $_}}
It "<Name> databases have all had a successful CheckDB within the last 7 days" -TestCases $testCases {
Param($Name)
$DBCC = Get-DbaLastGoodCheckDb -SqlServer $Name -Detailed
$DBCC.Status -contains 'New database, not checked yet'| Should Be $false
$DBCC.Status -contains 'CheckDb should be performed'| Should Be $false
}
}

We can save this as a .ps1 file (or we can add it to an existing Pester test file and call it will Invoke-Pester or just run it in PowerShell

05 - dbcc pester

As you can see you will still get the same warning for the availability group databases and we can see that SQL2012Ser08AG1 has a database whose status is CheckDB should be performed and SQL2012Ser08AGN2 has a database with a status of New database, not checked yet

That’s good, but what if we run our DBCC Checkdbs at a different frequency and want to test that? We can also test if the databases have had a successful DBCC CheckDb using the LastGoodCheckDb property which will not contain a Null if there was a successful DBCC CheckDb. As Pester is PowerShell we can use

($DBCC.LastGoodCheckDb -contains $null)

and we can use Measure-Object to get the maximum value of the DaysSinceLastGoodCheckdb property like this

($DBCC | Measure-Object -Property  DaysSinceLastGoodCheckdb -Maximum).Maximum
If we put those together and want to test for a successful DBCC Check DB in the last 3 days we have a test that looks like
Describe "Testing Last Known Good DBCC" {
$SQLServers = (Get-VM -ComputerName beardnuc | Where-Object {$_.Name -like '*SQL*' -and $_.Name -ne 'SQL2008Ser2008' -and $_.State -eq 'Running'}).Name
$testCases= @()
$SQLServers.ForEach{$testCases += @{Name = $_}}
It "<Name> databases have all had a successful CheckDB" -TestCases $testCases {
Param($Name)
$DBCC = Get-DbaLastGoodCheckDb -SqlServer $Name -Detailed
($DBCC.LastGoodCheckDb -contains $null) | Should Be $false
}
It "<Name> databases have all had a CheckDB run in the last 3 days" -TestCases $testCases {
Param($Name)
$DBCC = Get-DbaLastGoodCheckDb -SqlServer $Name -Detailed
($DBCC | Measure-Object -Property  DaysSinceLastGoodCheckdb -Maximum).Maximum | Should BeLessThan 3
}
}
and when we call it with invoke-Pester it looks like
06 - dbcc pester.PNG
That’s good but it is only at an instance level. If we want our Pester Test to show results per database we can do that like this
Describe "Testing Last Known Good DBCC" {
$SQLServers = (Get-VM -ComputerName beardnuc | Where-Object {$_.Name -like '*SQL*' -and $_.Name -ne 'SQL2008Ser2008' -and $_.State -eq 'Running'}).Name
foreach($Server in $SQLServers)
{
$DBCCTests = Get-DbaLastGoodCheckDb -SqlServer $Server -Detailed
foreach($DBCCTest in $DBCCTests)
{
It "$($DBCCTest.Server) database $($DBCCTest.Database) had a successful CheckDB"{
$DBCCTest.Status | Should Be 'Ok'
}
It "$($DBCCTest.Server) database $($DBCCTest.Database) had a CheckDB run in the last 3 days" {
$DBCCTest.DaysSinceLastGoodCheckdb | Should BeLessThan 3
}
It "$($DBCCTest.Server) database $($DBCCTest.Database) has Data Purity Enabled" {
$DBCCTest.DataPurityEnabled| Should Be $true
}
}
}
}
We gather the SQL instances into an array in the same way and this time we loop through each one, put the results of Get-DbaLastGoodCheckDb for that instance into a variable and then iterate through each result and check that the status is Ok, the DaysSinceLastGoodCheckDb is less than 3 and the DataPurityEnabled is true and we have
07 - dbcc pester.PNG

 

You can look at my previous posts on using Pester to see examples of creating XML files or HTML reports from the results of the tests.

Hopefully, as you have read this you have also thought of other ways that you can use Pester to validate the state of your environment. I would love to know how and what you do.

Happy Automating

NOTE – The major 1.0 release of dbatools due in the summer 2017 may have breaking changes which will stop the above code from working. There are also new commands coming which may replace this command. This blog post was written using dbatools version 0.8.942 You can check your version using

 Get-Module dbatools

and update it using an Administrator PowerShell session with

 Update-Module dbatools

You may find that you get no output from Update-Module as you have the latest version. If you have not installed the module from the PowerShell Gallery using

Install-Module dbatools

Then you can use

Update-dbatools

 

 

Getting SQLServers Last Known Good DBCC Checkdb with PowerShell and dbatools

As good SQL Server DBA’s we want to ensure that our databases are regularly checked for consistency by running DBCC CheckDB. This will be frequently scheduled using an Agent Job or by using Ola Hallengrens Maintenance Solution

We can check for the last known good DBCC Check using the undocumented DBCC DBINFO(DBNAME) WITH TABLERESULTS You can see the last known good DBCC Check around about row 50

00 - Using TSQL.PNG

This makes parsing the information a bit more tricky and whilst you could use sp_MSForEachDB to iterate through the databases that doesn’t always work as you expect as Aaron Bertrand explains

Of course, I am going to use PowerShell and also the dbatools module This module is a community based project written by excellent, brilliant people in their own time and available to you free. To find out more and how to use and install it visit https://dbatools.io

In the module there is a command called Get-DbaLastGoodCheckDb This command was created by Jakob Bindslet. You can find Jakob on his blog and on LinkedIn.

As always, you start with any PowerShell command by using Get-Help

get-help Get-DbaLastGoodCheckDb -ShowWindow

00a - get help.PNG

This command has three parameters Sqlserver, Credential and Detailed. Lets see what it looks like

Get-DbaLastGoodCheckDb -SqlServer SQLvNextN2

01 - One server

It returns an object with the server name, database name and the time and date of the last known good checkdb for every database on the server. What happens if we use the detailed parameter?

Get-DbaLastGoodCheckDb -SqlServer SQLvNextN2 -Detailed

 

02 - one server detailed.PNG

This time we get more information. The server name, database name, when the database was created, the last good DBCC Checkdb, how long since the database was created, how long since the last known good DBCC Checkdb, a status and a Data Purity enabled flag. If you look at the image above it shows that the DBA_Admin database has a status of “New database, not checked yet” even though it has a date for the last known good DBCC CheckDb. This is because it was restored after this server was upgrade from CTP 1.3 to CTP 1.4 and there has not yet been a DBCC CheckDb run yet. The system databases have a status of “CheckDb should be performed”. This is because the last known good DBCC CheckDb is more than 7 days ago. Lets run a DBCC CheckDb and check again

02a - one server.PNG

This time the status has changed to OK for all of the databases 🙂

We can pass an array of SQL servers to this command as well and check multiple servers at the same time. In this example, I am querying my Hyper-V server for all VMs with SQL in the name,except for my broken SQL2008 box ,that are running. I love PowerShell’s Out-GridView command for many reasons so lets use that. you can filter quickly and easily in the top bar.

$SQLServers = (Get-VM -ComputerName beardnuc | Where-Object {$_.Name -like '*SQL*' -and $_.Name -ne 'SQL2008Ser2008' -and $_.State -eq 'Running'}).Name
Get-DbaLastGoodCheckDb -SqlServer $SQLServers -Detailed | Out-GridView

03 - many servers ogv.PNG

As you can see, you get a warning for secondary availability group databases. It’s quick too. In my lab of 10 servers and 125 databases ranging from SQL2005 to SQL vNext it runs in a little under  5 seconds. This command is not compatible with SQL2000 servers.

04 - measure comand.PNG

It is important to remember that as this script uses the DBCC DBINFO() WITH TABLERESULTS, there are several known weak points, including:

– 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 LastKnownGood timestamp does not get updated when a database in READ_ONLY.

Databases created prior to SQL2005 and then upgraded to SQL 2005 or above need to have DBCC CheckDb run once with the DATA_PURITY option to ensure that the DATA_PURITY check ,which look for column values where the value is outside the valid range of values for the column’s data type, is run by default when DBCC CheckDB is run. This is explained more fully by Paul Randal here and Ken Simmons here The Data Purity Enabled flag from the command will show false if the data purity check is not being performed. This should be resolved by running DBCC CheckDB with DATA_PURITY option as explained here

Now with one line of PowerShell code you can check the last time a DBCC CheckDb was run for each database on one or more instances. The beauty of PowerShell is that an object is returned which you can use in any number of ways as shown in a previous post

Happy Automating

NOTE – The major 1.0 release of dbatools due in the summer 2017 may have breaking changes which will stop the above code from working. There are also new commands coming which may replace this command. This blog post was written using dbatools version 0.8.942 You can check your version using

Get-Module dbatools

and update it using an Administrator PowerShell session with

Update-Module dbatools

You may find that you get no output from Update-Module as you have the latest version. If you have not installed the module from the PowerShell Gallery using

Install-Module dbatools

Then you can use

Update-dbatools

 

Remove-SQLDatabaseSafely My First Contribution to DBATools

What is DBA Tools?

A collection of modules for SQL Server DBAs. It initially started out as ‘sqlmigration’, but has now grown into a collection of various commands that help automate DBA tasks and encourage best practices.

You can read more about here and it is freely available for download on GitHub I thoroughly recommend that you watch this quick video to see just how easy it is to migrate an entire SQL instance in one command (Longer session here )

Installing it is as easy as

which will get you over 80 commands . Visit https://dbatools.io/functions/ to find out more information about them

cmdlets

The journey to Remove-SQLDatabaseSafely started with William Durkin b | t who presented to the SQL South West User Group  (You can get his slides here)

Following that session  I wrote a Powershell Script to gather information about the last used date for databases which I blogged about here and then a T-SQL script to take a final backup and create a SQL Agent Job to restore from that back up which I blogged about here The team have used this solution (updated to load the DBA Database and a report instead of using Excel) ever since and it proved invaluable when a read-only database was dropped and could quickly and easily be restored with no fuss.

I was chatting with Chrissy LeMaire who founded DBATools b | t about this process and when she asked for contributions in the SQL Server Community Slack I offered my help and she suggested I write this command. I have learnt so much. I thoroughly enjoyed and highly recommend working on projects collaboratively to improve your skills. It is amazing to work with such incredible professional PowerShell people.

I went back to the basics and thought about what was required and watched one of my favourite videos again. Grant Fritcheys Backup Rant

I decided that the process should be as follows

  1. Performs a DBCC CHECKDB
  2. Database is backed up WITH CHECKSUM
  3. Database is restored with VERIFY ONLY on the source
  4. An Agent Job is created to easily restore from that backup
  5. The database is dropped
  6. The Agent Job restores the database
  7. performs a DBCC CHECKDB and drops the database for a final time

This (hopefully) passes all of Grants checks. This is how I created the command

I check that the SQL Agent is running otherwise we wont be able to run the job. I use a while loop with a timeout like this

There are a lot more checks and logic than I will describe here to make sure that the process is as robust as possible. For example, the script can exit after errors are found using DBCC CHECKDB or continue and label the database backup file and restore job appropriately. Unless the force option is used it will exit if the job name already exists. We have tried to think of everything but if something has been missed or you have suggestions let us know (details at end of post)

The only thing I didn’t add was a LARGE RED POP UP SAYING ARE YOU SURE YOU WANT TO DROP THIS DATABASE but I considered it!!

Performs a DBCC CHECKDB

Running DBCC CHECKDB with Powershell is as easy as this

you can read more on MSDN

Database is backed up WITH CHECKSUM

Stuart Moore is my go to for doing backups and restores with SMO

I ensured that the backup was performed with checksum like this

Database is restored with VERIFY ONLY on the source

I used SMO all the way through this command and performed the restore verify only like this

An Agent Job is created to easily restore from that backup

First I created a category for the Agent Job

and then generated the TSQL for the restore step by using the script method on the Restore SMO object

This is how to create an Agent Job

and then to add a job step to run the restore command

 

The database is dropped

We try 3 different methods to drop the database

The Agent Job restores the database

To run the Agent Job I call the start method of the Job SMO Object
Then we drop the database for the final time with the confidence that we have a safe backup and an easy one click method to restore it from that backup (as long as the backup is in the same location)
There are further details on the functions page on dbatools
Some videos of it in action are on YouTube http://dbatools.io/video
You can take a look at the code on GitHub here

You can install it with

You can provide feedback via the Trello Board or discuss it in the #dbatools channel in the Sqlserver Community Slack
You too can also become a contributor https://dbatools.io/join-us/ Come and write a command to make it easy for DBAs to (this bit is up to your imagination).