Tag Archives: 2016

Simple Stored Procedure to Compress Old Tables

Pretty sure the SQL Server compression code looks like this.

I’m always looking for a way to save space in SQL Server. From archiving old data to just flat out deleting unused objects, I take great joy in removing superfluous stuff. The less junk in the system, the easier it is to focus on the things that matter.

..and fit it in a 10 kg bag

The biggest useless space eaters are tables that are (supposedly) no longer used. I could script them with data to a file, but what if they’re 100+GB? I could also back them up to another DB and then drop them from the database; that would certainly free up the space in the original DB. What if they’re needed for some process that I was unaware of and we can’t wait for the time to restore/move them back?

My conundrum was this. So, I decided to implement a process that looked at a single DBA-controlled schema and compressed every table created prior to a certain date. I could TRANSFER the superfluous table to that schema, and leave it. At some point in the future a job would come along and compress it.

If the data was needed within X days, then the table could easily be transferred back to the original schema, no harm: no foul. Also, I would save space as tables would be automatically PAGE compressed and could be decompressed if needed. De/Compression is really fast in SQL Server.

It’s Compression Time

So, this super-simple stored procedure was created prCompressCleanupTables (click for github link). It takes the following parameters:

  • @CompressBeforeDate – A DATETIME variable that accepts how old the table must be before it is compressed (Looks at the created date)
  • @Schema – Sysname variable that takes the schema name that you want to compress. Keep in mind that this is the same schema for every database, so make sure it’s unique (I use the ‘Cleanup’ schema personally, hence the name).

It skips the following databases by default: master, tempdb, model, msdb, distribution, ReportServer, SSISDB. It will skip any database that is in any state other than ONLINE, too.

Also remember that compression is locked to certain editions of SQL Server, as well as being 2008+ (you really need to upgrade if being 2008 is a limiting factor).

I’m Also A Client

I have this implemented as a job on several servers which checks weekly for new tables to compress in the appropriate databases. It checks for any tables created prior to GETDATE() – 60. I have to say, that it runs very quickly even on large tables.

Let me know if this is helpful to you!

-CJ Julius

SQL Server on Linux: First 30 minutes

They put a ring on it.
They put a ring on it.

What I gushed over a few posts ago has finally happened! SQL Server has a come to Linux (sort of). The database engine is now available as CTP1 and you can get it by adding the repository and running the setup script.

You can follow the walk through for your favorite flavor of Linux, so I won’t repeat that here. it’s really very simple, just a matter of pointing to the correct repository and then apt-get install (Ubuntu). It comes with a setup script that pretty much does all the heavy lifting for you. Keep in mind that this is just for preview so there’s not a lot of options and it sticks everything in a single set of directories (logs/data/tempdb).

I had a small problem when I did the install, but it turned out I just needed to update a few packages. In the event you’re not a Linux person, here’s the easiest way to fix this:

$ sudo apt-get update
$ sudo apt-get upgrade

There’s a lot of stuff to dig into in this release, and as newer versions come out I’ll get more in-depth, but I just wanted to make a quick post about what I did in my first thirty minutes.

Behold in awe my INSERT abilities.
Behold in awe my INSERT abilities.

After the install, I connected via SQLCMD, as there is no SSMS in Linux yet, using the sa and sa password set in the install. I then created a table, dropping a single row into it and then selecting. Not terribly complex stuff.

I took care to try different cases, adding and neglecting brackets ‘[]’ and semicolons. It responded how I expected it to react if I was on a Windows system, which is very reassuring. It’s nice that my T-SQL skills translate seamlessly to the Linux environment, at least internally to SQL Server.

Connected via a my own username.
It doesn’t look or act any different than it I would have if connected to a Windows SQL Server instance.

Next, I put my box ‘U64’ on the network and lo-and-behold I was able to remote into it by its Linux hostname from SSMS 2016 on a Windows machine. No additional setup was required. Microsoft appears to be taking this integration of the Linux and Windows environments seriously.

I then created a SQL login for myself and logged in that way. No issues.

Now, as fun as this was, there’s a whole lot missing. The list includes, but is not limited to:

  • Full-text Search
  • Replication
  • Extended Stored Procedures
  • AD authentication
  • SQL Server Agent
  • SSIS
  • SSAS

This is of course just for CTP1, so a lot of these items will probably show up later. I mean, SQL Server without the SQL Server Agent? That doesn’t even make sense (I’m looking at you Express Edition). There is sort of cascade effect as other items like Maintenance Plans and such that rely on these missing features also being MIA.

The gang's all here!
The gang’s all here!

Also, larger items like Availability groups will also be absent because there’s no Linux analogue for them currently. From what the SQL Server team said in their AMA on reddit they’re toying around with RedHat clustering as a replacement for this in the Linux environment.

The last thing I did before the end of my 30 minutes was to look at the version. As you may or may not know, the Linux version is based on SQL Server vNext, which (as the name implies) is the NEXT version of SQL Server. There was some talk about it being a port of SQL Server 2016, which does not appear to be the case.

SELECT @@VERSION
----------------------------------------------------
Microsoft SQL Server vNext (CTP1) - 14.0.1.246 (X64)
Nov 1 2016 23:24:39
Copyright (c) Microsoft Corporation
on Linux (Ubuntu 16.04.1 LTS)

Note that SQL Server 2016 is version 13.0.

And that’s it! As mentioned before I’ll be doing deeper dives into this as time goes on, at the very least with each CTP. But I have to say I’m happy with the results so far. Everything (that was available) worked as I expected it to work. Nice work MS!

-CJ Julius

A Funny Thing Happened on my way to enable Management Data Warehouse

Three Job Schedules walk into a bar…
uh-oh
uh-oh.

Management Data Warehouse is a neat tool for collecting data on your instances with regards to performance, disk usage, and anything else related to SQL Server you might want to know. I’ve recently been rolling it out to various servers in test environments to get a good handle on all that it can do, and maybe more importantly, how it’s going to affect performance.

When I was satisfied that it was working the way I wanted in these environments, I started to push it to what you could call QA. Immediately I was hit with litany of errors, all of which said basically the same thing:

Caught error#: 14684, Level: 16, State: 1, in Procedure: sp_syscollector_create_collection_set, Line: 203, with Message: Caught error#: 14262, Level: 16, State: 1, in Procedure: sp_syscollector_create_collection_set, Line: 80, with Message: The specified @schedule_name ('CollectorSchedule_Every_30min') does not exist. (Microsoft SQL Server, Error: 14684)

Um, what? Of course it doesn’t exist, I’m installing it now. Just to verify, I did some poking around, and I found that it was indeed attempting to add a schedule that didn’t exist (as you would expect) to the collection set. After a while my Jr DBA (read: Google) turned up this article on removing MDW which says, in no uncertain terms:

The fact is that, while these schedules may look like they were created by MDW, they are created by default in a default installation of SQL Server 2008 or above. You can delete these easily, if you really want to, and if you are sure you will never enable MDW again. I would still suggest scripting the schedules and saving those scripts to your file system or source control so that you can recover them in the future.

I took a look back on the TEST instances where I was previously successful and found these schedules existed both on instances where MDW had been installed, and in places where it had not. These were part of the defaut SQL Server install and had been manually removed. Whoops.

As far as I know, there isn’t any direct way to script out schedules, so I could port them to the boxes where they had been removed. To get around this, I added them to the collector set jobs and then scripted that. Then I was able to change a few variables (and remove the schedule_uid) so that this:

EXEC @ReturnCode = msdb.dbo.sp_add_jobschedule @job_id=@jobId, @name=N'CollectorSchedule_Every_15min',
@enabled=0,
@freq_type=4,
@freq_interval=1,
@freq_subday_type=4,
@freq_subday_interval=15,
@freq_relative_interval=0,
@freq_recurrence_factor=0,
@active_start_date=20080709,
@active_end_date=99991231,
@active_start_time=0,
@active_end_time=235959,
@schedule_uid=N'SOME-GUID-HERE'

became this:

EXEC msdb.dbo.sp_add_schedule @schedule_name=N'CollectorSchedule_Every_15min',
@enabled=0,
@freq_type=4,
@freq_interval=1,
@freq_subday_type=4,
@freq_subday_interval=15,
@freq_relative_interval=0,
@freq_recurrence_factor=0,
@active_start_date=20080709,
@active_end_date=99991231,
@active_start_time=0,
@active_end_time=235959
GO

I ran these add_schedules on the QA boxes, went through the Configure Management Data Warehouse Wizard again, and tada!

Green means good.
Green is good. Green is life.

For your convenience, I’ve scripted out the four schedules I needed to get it going below. These are not from the most current version of SQL Server (2016 as of this writing), and are not all of the schedules included out of the box, but these let me get MDW running so I could add my own custom schedules for the remainder.

The moral of this story: Don’t remove MDW schedules unless you really mean it, for all time, forever and ever, pinky swear.

The four ‘core’ schedules I needed, for your convenience:

EXEC msdb.dbo.sp_add_schedule @schedule_name=N'CollectorSchedule_Every_6h',
@enabled=0,
@freq_type=4,
@freq_interval=1,
@freq_subday_type=8,
@freq_subday_interval=6,
@freq_relative_interval=0,
@freq_recurrence_factor=0,
@active_start_date=20080709,
@active_end_date=99991231,
@active_start_time=0,
@active_end_time=235959
GO

EXEC msdb.dbo.sp_add_schedule @schedule_name=N'CollectorSchedule_Every_30min',
@enabled=0,
@freq_type=4,
@freq_interval=1,
@freq_subday_type=4,
@freq_subday_interval=30,
@freq_relative_interval=0,
@freq_recurrence_factor=0,
@active_start_date=20080709,
@active_end_date=99991231,
@active_start_time=0,
@active_end_time=235959
GO

EXEC msdb.dbo.sp_add_schedule @schedule_name=N'CollectorSchedule_Every_15min',
@enabled=0,
@freq_type=4,
@freq_interval=1,
@freq_subday_type=4,
@freq_subday_interval=15,
@freq_relative_interval=0,
@freq_recurrence_factor=0,
@active_start_date=20080709,
@active_end_date=99991231,
@active_start_time=0,
@active_end_time=235959
GO

EXEC msdb.dbo.sp_add_schedule @schedule_name=N'RunAsSQLAgentServiceStartSchedule',
@enabled=1,
@freq_type=64,
@freq_interval=0,
@freq_subday_type=0,
@freq_subday_interval=0,
@freq_relative_interval=0,
@freq_recurrence_factor=0,
@active_start_date=20080709,
@active_end_date=99991231,
@active_start_time=0,
@active_end_time=235959
GO

If one of these schedules gets created twice you can look up the job id or use SSMS to ‘Pick’ the schedule for the duplicated schedule (the id is in the first column). And run this to remove it:

--EXEC msdb.dbo.sp_delete_schedule @schedule_id = 9999

-CJ Julius