What the Heck Is on Andy M Mallon - AM²

What the heck is the SSISDB? Where does it come from?

Mon, 18 Oct 2021 09:00:15 -0400

Back in my day, we stored SQL Server Integration Services (SSIS) packages in msdb, or the file system. Well, I’m neither dead nor retired, so that’s not an accurate statement–today is still “my time.” But when I was learning about SQL Server, those were the only two options. If you or your environment predate SQL Server 2012, then you might only be familiar with those two options.

What the heck is the dbcreator role?

Thu, 19 Dec 2019 07:30:14 -0500

Microsoft docs defines the dbcreator role as:

Members of the dbcreator fixed server role can create, alter, drop, and restore any database.

But what specific permissions are actually included in that role? If we scroll down in the docs just a little, we’ll see a diagram that tells us that dbcreator grants two permissions:

What the heck is Accelerated Database Recovery?

Mon, 21 Oct 2019 10:00:15 -0400

The intersection of Crash Recovery Boulevard and Version Store Avenue is now known as ADR Square. Last week, I wrote about the SQL Server Version Store. The week before, I looked at crash recovery. Let's look next at a new feature in SQL Server 2019, where these two features intersect: Accelerated Database Recovery.

What is it?

Accelerated Database Recovery(ADR) is a new feature intended to speed up the recovery process, which could be very slow, particularly when there are long-running, large transactions. ADR is not just for recovery after a crash, but also helps in other scenarios where the transaction log needs to be recovered–including Availability Group secondary redo and Failover Cluster Instance failovers.

What the heck is the SQL Server Version Store?

Tue, 15 Oct 2019 10:30:13 -0400

Sure, Microsoft does versioning, but check out this Microbus versioning!

Maybe you’ve read about the Read Committed Snapshot (RCSI) or Snapshot Isolation levels. Or maybe you were trying to figure out the difference between the two snapshot isolation levels. Perhaps you’ve looked into read-only secondary replicas in your Availability Group, or even had some problems with AG secondaries. Along the way, people and articles have mentioned this “version store” thing.

Recovery of database is 0% complete (approximately 1000000 seconds remain)

Sat, 12 Oct 2019 10:52:29 -0400

recovering from this crash is going to be pretty difficult

If you've ever had a server reboot unexpectedly, you've probably seen SQL Server start up, with some databases "stuck" in recovery status, then eventually they come online. Or maybe you thought "this session is stuck in rollback. It'll be quicker if I just reboot the server than wait for it to roll back!" ...only to find out that after restart, the database went into recovery, and you were left waiting impatiently for the database to come online.

In both of these scenarios, the database is going through the “crash recovery” status.

What the heck is downtime, anyway?

Mon, 15 Apr 2019 09:00:17 -0400

If a server falls in a data center and no users are around to notice, does it count as downtime? There's a lot of discussion about preventing downtime. As a DBA and IT professional, it's my sworn duty to prevent downtime. I usually describe my job as DBA something along the lines of, "to make sure data is always available to the people and applications that need it, and never available to the people and applications that shouldn't have it." Preventing downtime is certainly important for that first part--but how the heck do you define downtime?

What “downtime” means to most DBAs

When DBAs think about downtime, we often think in terms of “the server is offline” or “the database isn’t responding to queries” or even “the database isn’t responding to queries fast enough.” But is that really downtime?

What the heck is a DTU?

Thu, 30 Mar 2017 09:42:18 -0400

No, seriously. What is a DTU?

When you’re deploying any application, one of the first questions that comes up is “What will this cost?” Most of us have gone through this sort of exercise for sizing a SQL Server installation at some point, but what if you’re deploying to the cloud? With Azure IaaS deployments, not much has changed–you’re still building a server based on CPU count, some amount of memory, and configuring storage to give you enough IOPS for your workload. However, when you make the jump to PaaS, Azure SQL Database is sized with different service tiers, where performance is measured in DTUs. What the heck is a DTU?