Category: Administration

Matthew McGiffen explains that Accelerated Database Recovery in SQL Server 2019 works for more than just startup times:

If you’ve read about the Accelerated Database Recovery feature in SQL Server 2019 you could be forgiven for thinking it’s just about speeding up database recovery time in case of a server failure.

In fact, enabling it also means that where you have a long running transaction that fails or is cancelled the rollback is almost instantaneous. This is great news for DBAs who have to sometimes kill a long-running blocking transaction but worry that it may take a long time to rollback – continuing to block all that time.

Read on for an example. I hadn’t thought about this, but it’s pretty cool.

Thomas Rushton ran into an oddity with sys.dm_os_ring_buffers:

Wait! Process Utilization + Idle adds up to waaaaay over 100…What’s going on?

My first thought was that the CPU was being throttled, so I checked the windows power options – for some really irritating reason, Windows defaults to a “balanced” power setting, which is rubbish for SQL Server.

That looks OK, but… if you check the CPU page of the Task Manager, things are a bit more interesting:

Unfortunately, the story doesn’t have a conclusion, but Thomas’s conjecture does make sense.

Jack Vamvas takes us through what it takes to turn a read-write database in SQL Server read-only and vice versa:

There are some considerations for deciding if a Developer should be able to include as part of an ETL process , the capacity to change the READ STATE of a SQL database

1) Requires ALTER permission on the database. This is an elevated privilege – and may break the organisations sql server security policy

2) Is the developer on the hook for maintaining Production data? What is the developer’s role in supporting production data ?

Read on for the commands as well as additional considerations before you grant these permissions.

Josh Darnell takes us through how SQL Server manages ONLINE = ON operations (such as index building and rebuilding) using the version store:

The votes table has about 10 million rows in it, so this takes a bit of time (10-15 seconds if nothing else is happening). If I check sys.dm_tran_version_store_space_usage and sp_WhoIsActive, I can see that:

– the version store is not growing, and
– the ALTER statement is chugging along making progress

There are costs to setting ONLINE = ON. I think they’re almost always worth it, but it’s important to remember that they are there.

Ranga Babu has a few methods for starting SQL Server in single-user mode:

It is advisable to use SQLCMD when you want to query SQL Server that is started in single user mode as connecting directly and query using SQL Server Management Studio that uses more than one connection. To query SQL Server single user mode using SQL Server Management Studio, open SQL Server Management Studio, and do not connect to SQL Server directly. Close the connection window and click on New Query as shown in the below image which opens a query editor in SQL Server Management Studio:

I recommend practicing this a few times, as the only time you’d actually start SQL Server in single-user mode is during an emergency and that means people breathing down your neck (figuratively if not literally).

Andy Levy wraps up a Q&A series on dealing with thousands of databases:

When you started, did you know what your position was going to look like 1 month, 6 months, 1 year, 5 years from then? How accurate has that been so far?

I’ve only been at my current job for about 2 1/2 years, but I can speak to the shorter intervals. I’m going to be intentionally vague in spots here as I don’t want to disclose too much.

And if you’d like to hear Andy talk about migrating 8000 databases, Carlos Chacon and I interviewed Andy for the SQL Data Partners podcast.