Monday, 21 April 2014

Central Management Studio CMS

By David Postlethwaite

At my presentation on SQL Server Management Studio at SQL Saturday in Exeter I promised to write some articles on Gethyn’s blog about the bits I didn’t manage to cover.

One of the subjects I covered was Registered Servers and the Central Management Studio
These are two features in SSMS that allow you to register your SQL instances with a more meaningful name and then group them into folders such as project name or type.
This can make it much easier to find the instances used by a particular project especially for new starters who won’t know the names of all the instances and projects in your company.
The CMS can be shared by all of your DBAs or developers so there is one central list of instances and what they are used for.

One additional feature is the ability to run queries against multiple instances. You simply right click on a particular folder and select “New Query”. A new query window will open with a pink footer showing connected (x/x), where x is the number of instances in the folder.
Any query run in this window will execute on every instance in that particular folder.
If you select the CMS server itself you can run a query on every instance you have registered

A great feature you may think but what if you accidently ran this in a multi server query window?

exec sp_msforeachdb 'drop database [?];'

Since writing my presentation I have come across a DBA team that aren’t allowed to use the CMS because of the danger of accidently running a dangerous multi server query on every instance in the company.

I’ve hunted high and low but can’t find anyway of disabling the multi query option in SSMS so if you are not willing to risk it then the usefulness of the CMS will not be available to your team.

What do other think?
Does your company use the CMS?
Are the benefits of the CMS worth the risk of someone accidently running a dangerous multi server query?
Have you found a way of disabling the multi server query option?

Let me know?

Thursday, 17 April 2014

SSMS Auto Recovery

By David Postlethwaite

At my presentation on SQL Server Management Studio at SQL Saturday in Exeter I promised to write some articles on Gethyn’s blog about the bits I didn’t manage to cover.

SQL Server Management Studio will autosave your unsaved query every few minutes so if if your pc crashes you won’t have lost you work.
This is a similar idea to what we see in Word and Excel

Any new query will be added to the solution or project that is currently open. If you don’t have a solution open it will get save into a backup folder
My Documents\SQL Server Management Studio\Backup Files\Solution1

You can alter the recovery time
Tools -> Options -> Environment –> AutoRecover

 

image

There is a bug in Management Studio 2012 where the file must be saved first before it will starts to autosave it.
If you haven’t saved it at least once then it won’t autosave.

Management Studio 2008 and 2005 will autosave unsaved files without problem

Wednesday, 16 April 2014

From where does SSMS get its database defaults?

We can create a database simply by typing in the command

create database DB1 



We don’t have to provide any other parameters for SSMS to be able to create the database

My Question is from where does SQL get the default values when we create a database without any options?
We have always assumed that is was from the model database.

Here’s an interesting exercise:

Create an empty database using the command above and make a note of its size and autogrowth values.
Compare these to those of the model database. Assuming you have never changed the model database you’ll find they are identical.

Change the initial size and the autogrowth values in the model database to something obviously different.
Now create a new database DB2 with the script

create database DB2 



Take a look at the size and autogrowth of the new database and compare them to the values you put in the model database. The data file size will probably match but the rest will have taken the original values you saw in the model database.

SSMS hasn’t used the values in the model database which is what we all assumed it would do

Now create a database using the GUI
You will see in the GUI that the new database has taken its values from the model database
It seems that SSMS only uses the model database as its template when you use the GUI, you cannot guarantee the values that will be used when using a simple script
Which is why its best practice is to include all the parameters when creating database.

In case you need to reset mode back to the SQL defaults then run this

USE [model]
GO
DBCC SHRINKFILE (N'modeldev' , 3)
GO
DBCC SHRINKFILE (N'modellog' , 1)
GO
USE [master]
GO
ALTER DATABASE [model] MODIFY FILE ( NAME = N'modeldev', FILEGROWTH = 1024KB )
GO
ALTER DATABASE [model] MODIFY FILE ( NAME = N'modellog', FILEGROWTH = 10%)

Monday, 14 April 2014

Missing Database Owner

By David Postlethwaite

At my presentation on SQL Server Management Studio at SQL Saturday in Exeter I promised to write some articles on Gethyn’s blog about the bits I didn’t manage to cover.

image

A scenario
A DBA creates a new database and by doing so he become the owner of that database.
He then leaves the company and his Windows account is deleted.
When you try to view the database properties in SQL Server Management Studio you will receive the error “Property Owner is not available”

When SSMS tries to open the database it check the permissions of the owner and because it can no longer find it in Active Directory it aborts the request

You will not be able to view the properties until a new owner is assigned.
This is quite simple just issue this command on the database

sp_changedbowner 'sa' 



You cannot just create a new Windows user with the same name. The underlying SIDs will not match.

If the owner of the database is a SQL user then it’s not possible to delete that user but SQL Server can’t manage Active Directory so is unaware when an account has been deleted.

Also note that if the owner of an SQL Agent job is deleted that Agent job will not run because, once again, SQL checks the permissions of the owner and can’t find it in AD so will not continue.

To avoid this scenario it is best practice to ensure that all databases and agent jobs are owned by “sa” unless there is a good reason not to.

Thursday, 10 April 2014

Alter Table Not Permitted

By David Postlethwaite

At my presentation on SQL Server Management Studio at SQL Saturday in Exeter I promised to write some articles on Gethyn’s blog about the bits I didn’t manage to cover.

image

You may have come across this error message when using SQL Server Management Studio

It’s new in SSMS 2008.
You cannot, by default, make changes to a table that will require it to be dropped and re-created.
These changes are
Changing data type on existing columns
Or changing allow nulls on existing columns
Or changing order of columns

But you can turn this behaviour off
Tools Menu -> Options -> Designers
Untick "prevent saving changes that require table re-creation"

But beware.
If it is a table with large amount of data it could take some time to copy it from the old to the new table

Wednesday, 9 April 2014

Dedicated Administrator Connection

By David Postlethwaite

At my presentation on SQL Server Management Studio at SQL Saturday in Exeter I promised to write some articles on Gethyn’s blog about the bits I didn’t manage to cover.

If a SQL instance isn’t responding or you can’t login for some reason then SSMS has a back door called the Dedicated Administrator Connection or DAC.
The DAC uses a special reserved scheduler which has one thread for processing requests.
This essentially means that SQL Server is keeping a backdoor open just for this purpose.

To login using the DAC you must be a member of the sysadmin server role.
By default, for security, you can only use this from the local server, not from a remote connection.
You can enable remote connections using the command

sp_configure 'remote admin connections', 1



To use the DAC, in the SSMS connection window prefix the name of the server with “admin:”


image


You can’t connect using Object Explorer because it only allows one thread so you must use the Query Window Only

Only one use one admin connection at a time can use the DAC so if another DBA tries to connect using the admin option they will get an error

Also, you should only run simple, quick queries using the DAC.

If you are connecting remotely you many need to get firewall ports opened as well, depending on your environment.
This will probably be port 1434, but that will vary depending on your configuration.

SQLcmd also supports DAC
Sqlcmd – A

Check that you can use the DAC before you need to use it for real and that you have handy whatever admin scripts you require because, remember, you can’t use object explorer to help you diagnose your problem instance.

Monday, 7 April 2014

SQL Saturday Exeter

A couple weeks back was the second SQL Saturday to be held in Exeter. Although I wasn’t speaking this time, my friend, colleague and fellow contributor to this blog, David Postlethwaite was making his full speaking debut delivering a session entitle “Real DBAs Don’t need a GUI” it was a look at all the features of SQL Server Management Studio that you may not know existed. Unfortunately I was poorly on the day of the event and couldn’t make the session, but David did rehearse his talk with me and it went very well. It seems that his audience agreed and everyone seemed to give him positive feedback. It seems that the whole day was pretty successful and hopefully there will be another SQL Saturday in Exeter next year.

It seems David has caught the speaking bug so to speak. He has come back from Exeter and is keen to expand on this experience. He has put together two further talks. One on Oracle for the SQL Server DBA and another one called “Taming the Beast – How a SQL DBA can keep Kerberos under control.” He has submitted these sessions along with his SSMS talk to several SQL Saturdays around Europe.

Kerberos

If you are organising a SQL Saturday event and you have seen that David has submitted a session then maybe, just maybe, you can invite him along and he can show you how to “tame the beast” :D

Following on from David’s talk on SSMS, he was not able to cover everything in the 50 minute slot so he has kindly put together some blog posts covering the material and topics he was not able to get to during his talk. These will be published over the next few weeks, so stay tuned for more SSMS goodness from David P.