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Day: July 28, 2017

Querying MSDB For Backup Information

Published 2017-07-28 by Kevin Feasel

Lori Brown shows how to query the msdb database and get information on backups, including whether the backups are compressed:

We recently started using a third party software to do our in-house SQL backups so that the backup files are stored in a redundant and safe place. To confirm that the software was indeed compressing backups as it stated it would, we wanted to see what each backup size actually was in SQL so that we could compare that to what the software was telling us.

SQL stores lots of handy backup information in msdb in the backupset and backupmediafamily tables.

There’s some useful information in these tables, though make sure you clean them up regularly or else msdb can become enormous.

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R6 Classes In R

Published 2017-07-28 by Kevin Feasel

David Smith explains what R6 classes are in R:

The big advantage of R6 is that it makes it much easier to implement some common data structures in a user-friendly manner. For example, to implement a stack “pop” operation in S3 or S4 you have to do something like this:

x <- topval(mystack)
mystack <- remove_top(mystack)

In R6, the implementation is much simpler to use:

x <- mystack$pop()

David links to some good resources on the topic, so check those out as well.

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Finding Running Agent Jobs

Published 2017-07-28 by Kevin Feasel

Adrian Buckman has a script to find all running SQL Agent jobs:

For our Procedure we wanted to show currently running jobs regardless of run time or run time vs historical run time, we also wanted to be able to see if the job was started by the Agent itself or a User, and to see which step the job is currently running on including that steps Elapsed time and last but not least the Total job elapsed time.

Now I will be the first to admit , this is not the prettiest code I have ever produced but getting some of this information out is quite tricky 🙂

This Procedure is a great alternative to the SQL Agent Activity Monitor, it doesn’t have all the information that the Monitor has but it probably has everything that you need to see at a glance – and whats more being that it is a Stored Procedure you could run this across multiple servers via registered servers for example and get results within seconds.

Click through for the script.

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Powershell To Copy Reporting Services Subscriptions

Published 2017-07-28 by Kevin Feasel

Claudio Silva has a new contribution to the Reporting Services Powershell module:

If we take a look to the “New Subscription” form, we will discover about a dozen of fields that need to be configured. Doing this by hand can make you want to pull your hairs, also the probability of error is huge, even with copy & paste.
Who wants to do copy & paste of dozens of fields between reports? I know who doesn’t – me 🙂

Click through to learn more about Claudio’s cmdlets for getting, setting, and removing Reporting Services subscriptions.

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Moving TempDB In Linux

Published 2017-07-28 by Kevin Feasel

David Klee shows how to migrate the tempdb database when running SQL Server on Linux:

We previously created a folder at /var/opt/mssql/data/tempdb01 for these files. Moving them is straightforward, once you know the file system structure. The following commands will move them to the new location, and I also add additional files to equal the four vCPUs I have on this SQL Server VM. The file growth is my model database’s default of 64MB for this instance. Do as you would normally do with SQL Server on Windows with tempdb file counts and separation of duties for your workload.

Read on for the process.  As a general spoiler, the “how to do this in Linux” answer is usually pretty close to the same as the “how to do this in Windows” answer, at least once you get into Management Studio.

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The Risks Of Clearing The Procedure Cache

Published 2017-07-28 by Kevin Feasel

Erin Stellato explains two downsides to running DBCC FREEPROCCACHE or anything else which clears query plans:

Ideally, you should remove only what’s absolutely necessary.  Using DBCC FREEPROCCACHE is a sledgehammer approach and typically creates a spike in CPU as all subsequent queries need to have their plans re-generated.  Glenn gives examples on how to use each statement (and others) in his post Eight Different Ways to Clear the SQL Server Plan Cache, and I want to show you one more thing that happens when you clear a plan (or all plans) from cache.

For this demo script, I recommend running it against a TEST/DEV/QA environment because I am removing plans from cache which can adversely affect performance.

There are reasons to run these commands, but ideally, you should be as precise as possible in clearing plans out of the cache.

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