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Category: Administration

Don’t Rebuild Heaps

Published 2016-01-15 by Kevin Feasel

Steve Jones notes the issues around rebuilding tables lacking clustered indexes:

What about adding a clustered index and dropping it? Nooooooo, and again, I learned something new. This causes two rebuilds of the non-clustered indexes as they are rebuilt with the cluster addition and then rebuilt when the table changes back to a heap (to get the heap locations). That’s crazy, and certainly not what we want.

Also read Matthew Darwin’s comment, as “Don’t do X” usually has an “Except when Y” corollary.

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Automated Database Shrinking

Published 2016-01-15 by Kevin Feasel

Chris Shaw talks about auto-shrink:

If you are new to being a Database Administrator or the Primary focus of your job is not to be a DBA you may see the benefits of shrinking a database automatically.  If the database shrinks by itself, it might be considered self-management; however, there is a problem when doing this.

When you shrink a data file SQL Server goes in and recovers all the unused pages, during the process it is giving that space back to the OS so the space can be used somewhere else.  The downstream effect of this is going to be the fact your indexes are going to become fragmented.  This can be demonstrated in a simple test.

Friends don’t let friends auto-shrink.

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Pausing The SQL Server Service

Published 2016-01-14 by Kevin Feasel

Tom LaRock shows us that we can pause the SQL Server service, as well as what that gets us:

By pausing the SQL Server service before restarting the instance we allow end users to continue their work uninterrupted and we also stop any new connections to the instance. This is a nicer way of telling people to “get out” of the database in order for the server to be rebooted. I wouldn’t leave the server paused for 60 minutes of course, but I would rather use this method than forcibly disconnect users and rollback their transactions.

This is a nice way of bleeding the service dry before taking an instance down for maintenance.

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Fixing SQL Server R Services Installation Issues

Published 2016-01-14 by Kevin Feasel

Cody Konior notes that upgrading from CTP 3.0 to CTP 3.2 can cause SQL Server R Services to break:

If you were using CTP 3.0 and later ran an in-place upgrade to CTP 3.2 this will silently break R Services. Uninstalling and reinstalling the R component will not fix the problem, but it can be fixed. There are a few interrelated issues here so bear with me.

Hopefully you don’t run into this issue, but if you do, at least there’s a fix.

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Who Grew The Database?

Published 2016-01-14 by Kevin Feasel

Andy Galbraith helps us figure out who to blame for database growth:

I feel a little dirty writing about the Default Trace in the world of Extended Events, but I also know that many people simply don’t know how to use XEvents, and this can be faster if you already have it in your toolbox.  Also it will work back to SQL 2005 where XEvents were new in SQL 2008.

I have modified this several times to improve it – I started with a query from Tibor Karaszi (blog/@TiborKaraszi), modified it with some code from Jason Strate (blog/@StrateSQL), and then modified that myself for what is included and what is filtered.  There are links to both Tibor’s and Jason’s source material in the code below.

I usually just blame the BI team for database growth.

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Planning SQL Server Migrations

Published 2016-01-14 by Kevin Feasel

Kendra Little has some great resources to get you started with a SQL Server migration:

Planning to move to new hardware for your SQL Server? Techniques like log shipping and database mirroring can be incredibly useful to make the change fast and painless– but you’ve got to pick the right techniques for your environment ahead of time, and know how to do a few things that aren’t in the GUI.

Some of this stuff could also feed into a disaster recovery plan.

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Restoring An Azure SQL Database

Published 2016-01-12 by Kevin Feasel

Grant Fritchey shows us how to restore a database hosted in Azure SQL Database:

The first, and most important thing to notice here is that it’s supplying me with a new name. I can change that to anything I want as long as it’s not the name of a database already in existence on my Azure SQL Database Server. You read that correctly, you can restore a database to Azure SQL Database, but there is no WITH REPLACE option. The restore creates a new database. This is important. In a recovery scenario, you need to be sure that you’re prepared to deal with this fact. How could you replace the existing database? Immediately run a pair of ALTER DATABASE commands to change the name of the existing database to something else and then change the name of your newly created database to the old name. That’s your choice.

There are a couple of gotchas, so if you are administering Azure SQL Database instances, be aware of these.

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Installing TFS

Published 2016-01-12 by Kevin Feasel

Sifiso Ndlovu shares some tips regarding installing Team Foundation Server:

Although, you can get away with using convenience names (i.e. a dot, (local), or locahost) as SQL Server identifier name during the configuration of a SharePoint server farm as shown in Figures 2 & 3, such a practice is not allowed during configuration of TFS (as shown in Figure 1).

Check this out before installing your own TFS server.  Or use Visual Studio Online or GitHub or BitBucket or …

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Compess An Entire Database

Published 2016-01-11 by Kevin Feasel

Shaun J. Stuart has a script which compresses all (compression-worthy) objects in a database:

Reader Dick H. posted a comment on my last version of this script stating that he got an error when this was run against tables containing sparse columns. Data compression does not support tables with sparse columns, so they should be excluded from this process. I’ve modified this script to correct this. I don’t have any tables with sparse columns in my environment, so thanks to Dick for pointing this out!

For instructions on using this script, look here.

This is a very useful script to have in your back pocket.

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Row-Level Security

Published 2016-01-11 by Kevin Feasel

Manoj Pandey investigates row-level security:

Here in this post I will talk about the new Block Predicate option available in the CTP 3.0 release. With this option we can restrict write access for specific users.

Block Predicates block all write operations like:

– AFTER INSERT and AFTER UPDATE

– BEFORE UPDATE

– and BEFORE DELETE

I want this to perform well in a busy production environment.  I really, really do.

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