Tag Archives: automatic tuning

Top 5 New Features in SQL Server 2017 (that I care about)

New Year, New Database Engine

This is either a database or a stack of licorice pancakes.

It’s finally here! A few days ago as of this writing, SQL Server 2017 was released for Windows, Ubuntu, RedHat and Docker. There are a lot of new things in SQL Server 2017 from Python support in Machine Learning* to better CLR security. But I thought I’d narrow down the list to changes that I’m most interested in.

1. sudo Your Way To A Better SQL Server

SQL SERVER IS ON LINUX NOW! No surprise this is the first thing on my list as I keep going on and on about it. But it’s really here!

Installation is a cinch, especially if you’re a Linux or Unix person. Curl the GPG keys, add the repository, apt-get (if you’re on a real Distro) the installer and run the setup. It’s really that easy.

If you want it even easier, then check out Docker. Slap it in and go!

All the main features are there, the engine (of course), agent, Full-text search, DB Mail, AD authentication, SQL command-line tools etc. Pretty much everything you need to get going on Linux even if you’re in a Windows-dominated environment.

2. It’s Like A Car That Repairs Itself

So this is a big one. With automatic tuning on, SQL Server can detect performance problems, recommend solutions and automatically fix (some) problems. There are two flavors of this, one in SQL Server 2017 and one in Azure; I’ll be talking about the one in SQL 2017 here.

Automatic plan choice correction is the main feature and it checks whether a plan has regressed in performance. If the feature is so enabled, it reverts to the old plan. As you can see below, a new plan was chosen (4) but it didn’t do so well. SQL 2017 reverted to the old plan (3) automatically and got most of the performance back.

Image Source: Microsoft

I’m sure that Microsoft will be expanding this feature in the future and we can expect to see more from this. Azure already has automatic Index tuning in place, so we’ll probably see that in the On-Prem version eventually.

3. Indexes That Start, Stop And Then Start Again

This is a feature I didn’t know I needed. Basically, it allows an online index rebuild that has stopped or failed (say, it ran out of disk space) to be resumed. The index build fails, you fix whatever made it fail, and then resume the rebuild, picking up from where it left off. The rebuild will be in the ‘PAUSED’ state until you’re ready to RESUME or ABORT it.

-- Start a Resumable index rebuild
ALTER INDEX [NCIX_SomeTable_SomeColumn] on [dbo].[SomeTable]

-- PAUSE the rebuild:
ALTER INDEX [NCIX_SomeTable_SomeColumn] on [dbo].[SomeTable] PAUSE

/* If you'd like to resume either after a failure or because we paused it. This syntax will also cause the resume to wait 5 minutes and then kill all blockers if there are any. */
ALTER INDEX [NCIX_SomeTable_SomeColumn] on [dbo].[SomeTable]

/*Or if you just want to stop the whole thing because you hate unfragmented indexes */
ALTER INDEX [NCIX_SomeTable_SomeColumn] on [dbo].[SomeTable] ABORT

This is also great if you want to pause a rebuild because it’s interfering with some process. You can PAUSE the rebuild, wait for the transaction(s) to be done and RESUME. Pretty neat.

4. Gettin’ TRIM
A cute Sheepy.
There hasn’t been a picture in a while and I was afraid you might be getting bored.

This one is kind of minor, but it excited me a lot because it was one of the first things I noticed as a DBA that made me say ‘Why don’t they have a function that does that?’ (note the single quotes). TRIM will trim a string down based on the parameters you provide.

If you provide no parameters it will just cut off all the spaces from both sides. It’s equivalent to writing RTRIM(LTRIM(‘ SomeString ‘))

SELECT TRIM( '.! ' FROM ' SomeString !!!') AS TrimmedString;


5. Selecting Into The Right Groups

Another small important change. In previous versions of SQL Server, you could not SELECT INTO a specific Filegroup when creating a new table. Now you can, and it uses the familiar ON syntax to do it.

SELECT [SomeColumn] INTO [dbo].[SomeNewTable] ON [FileGroup] from [dbo].[SomeOriginalTable];

Also, you can now SELECT INTO to import data from Polybase. You know, if you’re into that sort of thing.

Honorable Mentions!

Here are some things that caught my eye, but didn’t really need a whole section explaining them. Still good stuff, though.

Query Store Can Now Wait Like Everybody Else

Query store was a great feature introduced in SQL Server 2016. Now they’ve added the ability to capture wait stats as well. This is going to be useful when trying to correlate badly performing queries and plans with SQL Server’s various waits.

See the sys.query_store_wait_stats system table in your preferred database for the deets. Obviously, you’ll need to turn on Query Store first.

Con The Cat With Strings

Just as minor as TRIM in some people’s books, but this is a great function for CONCAT_WS’ing (it’s not Concatenating, right? That’s a different function) strings with a common separator, ignoring NULLs.

SELECT CONCAT_WS('-','2017', '09', NULL, '22') AS SomeDate;


Get To Know Your Host

sys.dm_os_host_info – This system table returns data for both Windows and Linux. Nothing else, just thought that was neat.

Get Your Model Serviced

Not something I’m jumping for joy about, but it is a good change of pace (I think). No more Service Packs, only Zuul… er… just Cumulative Updates. Check out my article on it if you want to know more about all the Service Model changes.

And Lots Of Other Things

Of course, there’s hundreds other things that are in SQL Server 2017 and related features. I didn’t even touch on the SSIS, SSAS, SSRS, MDS or ML stuff. Check out the shortened list here, broken down by category. Exciting new toys!

-CJ Julius

* Seriously, how do you release a Data Science platform and not include Python? That’s like releasing a motorcycle with only the rear tire. Yes, you can technically use it, but you you’re limiting yourself to a customer base with a very selective skill-set.