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Category: T-SQL Tuesday

Waiting For SP1

Published 2016-06-15 by Kevin Feasel

Guy Glantser hates “wait for SP1” advice:

Historical Facts

Throughout my career I have never seen an RTM version that was substantially less stable then the following SP1. Sure, there were bugs and issues. Sometimes there were critical bugs and issues. But there were just as much bugs and issues in SP1 and in SP2, and so on. I haven’t conducted a thorough research, so I don’t have a statistical proof, but these are the facts, at least from my experience.

I’d add one more thing:  pre-release versions of SQL Server run in production as part of Microsoft TAP (older link, and I think RDP and TAP have merged together at this point, but I don’t have those inside details).  These are real companies with real workloads running pre-RTM versions of SQL Server.  I work for a company which is in the program, and we were running our data warehouse on CTP 3 and then RCs.  By the time RTM hits the shelves, there’s already been a good deal of burn-in.

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T-SQL Tuesday: SQL 2016

Published 2016-06-08 by Kevin Feasel

Michael J. Swart is hosting this month’s T-SQL Tuesday:

SQL Server 2016 went RTM this week and so naturally, we’re going to write about it. Here are a few writing prompts for you:

  • Check out what’s new. Microsoft has written a lot about their new features. Thomas Larock has written a really nice landing page for those posts, SQL Server 2016: It Just Runs Faster – Thomas Larock. Look through those links. Do you feel optimistic about 2016? Or maybe a bit disappointed? Let us know either way

  • Haven’t had time to download the bits, install them, explore and form thoughts on 2016 yet? Have no fear, check out Microsoft’s Virtual Labs. It lets you explore features without worrying about all the setup. In minutes you’ll be typing SELECT 'hello world';

Get writing!

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RID Lookup Or Key Lookup?

Published 2016-05-11 by Kevin Feasel

Aaron Bertrand asks which is faster, RID lookups or key lookups?

I’ve seen multiple people state that a heap can be better than a clustered index for certain scenarios. I cannot disagree with that. One of the interesting reasons I’ve seen stated, though, is that a RID Lookup is faster than a Key Lookup. I’m a big fan of clustered indexes and not a huge fan of heaps, so I felt this needed some testing.

So, let’s test it!

I thought it would be good to create a database with two tables, identical except that one had a clustered primary key, and the other had a non-clustered primary key. I would time loading some rows into the table, updating a bunch of rows in a loop, and selecting from an index (forcing either a Key or RID Lookup).

It looks like RID lookups are slightly faster than key lookups.  But check out the comments:  this is a best-case scenario.

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Custom Power BI Visuals

Published 2016-05-11 by Kevin Feasel

Rob Farley looks into custom Power BI visuals:

I hadn’t explored much in the way of custom visuals in Power BI until a while back, even though I was very much aware of the competition that was held in September. It had been on my list to explore some of what was possible. And this month, the T-SQL Tuesday topic (hosted by Wendy Pastrick – @wendy_dance) was to learn something new and to blog about it. So it seemed a good idea to learn how to make my own custom visualisation!

Now, creativity isn’t exactly my thing. I find it really hard to write songs, for example. I know how to do it – but I quickly become self-critical and get stuck. Writing is easier, because it feels less ‘creative’, and appeals more to the teacher / preacher in me (and I know that takes creativity, especially if you’ve ever seen me present, but it’s different). So sitting down and coming up with a new way of visualising data wasn’t something I was going to do.

For more info, check out more info on creating visuals and using R to visualize data in Power BI.

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DB File Space Usage

Published 2016-05-11 by Kevin Feasel

Andy Mallon looks into sys.dm_db_file_space_usage:

SQL Server 2016 is coming out next month, and it’s chock full of new features that I can learn. Row-level security is interesting. Dynamic data masking sounds fun.

If you’re a regular reader of my blog, you probably know I try to approach questions from a unique angle. Instead of blogging about something cutting edge or sexy, I decided to scroll through the list of system views until I found one I didn’t recognize.

sys.dm_db_file_space_usage

The name is pretty self-explanatory, but I never noticed this existed until now. Seems like the type of DMV that I should have known about, but I didn’t. Quick look at BOL, and I got the verbose description from Microsoft:

Andy goes on to compare the outputs from this DMV to methods he’s historically used.

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T-SQL Tuesday Roundup

Published 2016-04-18 by Kevin Feasel

Jens Vestergaard has his round-up of favorite SQL Server features:

This week, I have been looking forward to the time where I got to read through all the contributions to my#TSQL2SDAY invitation: Favorite SQL Server Feature. Very happy to see this many. I have added a short description of each blog post, as well as my own personal key take-away(s).

So, in no particular order, I give you the round-up:

I like T-SQL Tuesday for several reasons; one of the more selfish reasons is that each month, I get to expand my blogroll a little bit further.  This was a particularly good one, so check out the entrants.

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Partition Switching

Published 2016-04-15 by Kevin Feasel

James Anderson gives his favorite feature in SQL Server:

The good news is that the SWITCH command works on regular tables and in any edition. This means I can quickly transfer all of the data from one table to another in Standard Edition.

In reality, I have found few uses for the regular table to regular table switch; the trick to add the IDENTITY property to a column with existing data is the most recent. SWITCH is most useful when partitioned tables are involved. Sorry, Standard Edition users.

Partition switching is a fascinating solution for a difficult technical problem.

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DMVs

Published 2016-04-14 by Kevin Feasel

Andy Yun talks about his favorite SQL Server feature:

Much earlier in my SQL Server career, I never knew much about how SQL Server operated under the hood. I only had knowledge of the things I could do directly, but I never questioned what was really happening behind the scenes. Then I attended SQLskills IE1 training, which was a turning point in my career. Among other things, it was my first exposure & deep dive into SQL Server Internals. I became enamored with learning how things really worked under the hood and the DMVs/DMFs became one of my best friends.

This is a big part of SQL Server administration.  It boils down to asking the server where it hurts and understanding how it responds.  DMVs are extremely helpful in that regard.

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Restraint

Published 2016-04-14 by Kevin Feasel

Andy Mallon comes out of left field with his favorite feature:

It’s really tempting to implement cool-sounding features. It’s really tempting to hyper-tune solutions to be the absolutely perfect, most-optimal solution. But it takes a real expert to realize when you’re over-engineering a solution.

Take a moment to appreciate your own restraint. Appreciate all the features that you didn’t implement because you didn’t have to. Be happy that you looked at the big picture and decided the best solution was the one you were able to support.

It’s definitely an interesting approach to the T-SQL Tuesday challenge, so full credit for that.

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Azure Transactional Replication

Published 2016-04-14 by Kevin Feasel

John Sterrett names transactional replication into Azure as his favorite feature:

In the field, I see a lot of people using Availability Groups to have a near real-time replica for reporting.  I talked a little bit about this above.  What isn’t mentioned here is you have to maintain a Windows Failover Cluster, Quorum, Active Directory (Unless using Windows 2016 Preview) and more. This gets you a replica that is just a copy of the database. What does this mean? You cannot change database objects like security, indexes, etc. Also, what if you don’t need the whole database(s) for reporting? If not, you can replicate only the data you truly need.

So, let’s recap here.  You only have to replicate the data that you need.  You can have different security and indexes on your reporting subscriber database(s).  The reporting subscriber database can be scaled up or down as needed based on your needs.  The reporting database can now be an Azure Database. Folks, I call this a huge win!

There’s a lot more replication love out there than I’d expect.  John promises to follow up with a guide on how to implement this, so keep an eye out for that.

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