Did you know that SQL Server tracks suspect pages and puts the details into the msdb database in a table called suspect_pages? Well it does, but the question I want answering is what happens if the page within the suspect pages table is fixed? Does it automatically get removed/updated or do we as the administrators have to do anything manually?
Let’s find out.
It’s a useful table to monitor.
A very common requirement which can be satisfied by various tools. Personally I like using Visual Studio 2017 Community Edition and I thought I would do a quick overview of it.
First thing, you can find the download from this link: https://www.visualstudio.com/downloads/ and once installed (making sure that you select SQL Server Data Tools) go find Visual Studio 2017 and you will be presented with your start screen.
Click through for the process. This tool is nice for one-off jobs, like when you want to synchronize production down to source control or see the differences between two environments. But if you’re doing these comparisons a lot, I think you’re better off scripting it out using SMO and Powershell.
Clearly I am in a paused state with 5.48% percent of the operation complete. In the original query window where I started the index rebuild, I receive:
Msg 1219, Level 16, State 1, Line 4 Your session has been disconnected because of a high priority DDL operation. Msg 0, Level 20, State 0, Line 3
A severe error occurred on the current command. The results, if any, should be discarded.
DTUs when in a paused state, it drops back down to pretty much 0 DTU consumption (red arrow below).
If you have a hard nightly maintenance window to hit, being able to pause index rebuilds is a pretty nice feature.
I was exchanging messages with Azure Support and even though I didn’t get a concrete answer to confirm this I ended up asking the question within a Microsoft based yammer group and yes they do automatically carry out consistency checks.
This is great but it is one less thing for me to worry about and if there is serious corruption, you know potential data loss (which would be rare) then they will definitely tell you and work with you.
However, it doesn’t mean you CAN’T run it, I was curious so I ran DBCC CHECKDB on my Azure SQL Databases, but like with any other consistency check it is best to do it OFF-PEAK hours. I would probably take it a step further and wouldn’t even bother running it.
It’s an interesting post, reminding us that administering an Azure database isn’t the same as on-prem.
Quite a mouth full for a title but never the less very exciting. With the new version of SQL Server Management Studio (SSMS) 17.2 You now have the option to use Azure AD authentication for Universal Authentication with Multi-factor authentication (MFA) enabled, by that I mean use a login via SSMS that is enabled for MFA where below I will show you the two step verification using a push notification to my iPhone. (Yes iPhone I love it)
Download SSMS 17.2 from this link. https://docs.microsoft.com/en-us/sql/ssms/download-sql-server-management-studio-ssms
Once installed you will see new Authentication options, the option that I want is the one highlighted below – “Active Directory – Universal with MFA support”
Click through for a demo of this. I wonder if (when?) something like this comes to on-prem, maybe in conjunction with a third-party multi-factor authentication service.
We should all be aware that when changing the service tier and/or performance level of a database it creates a replica of the original database at the new performance level and then switches connections over to the replica. No data is lost during this process but during the brief moment when we switch over to the replica, connections to the database are disabled, so some transactions in flight may be rolled back. So it probably best that you do this during a period of low activity.
It’s pretty easy to do, but heed Arun’s warning, as you can cause queries to fail during switch-over. My experience has been that scaling up is pretty slow, too: I seem to recall it taking 10-20 minutes for a moderately sized database.
The answer is via Azure Automation.
At a high level this is what I did.
Create an Automation Account.
Create a credential.
Create a PowerShell Runbook which has the code for index rebuilds.
Create a schedule and link it to the above.
Configure parameters within the schedule (if any).
Configure logging level (if desired).
Click through for the detailed steps.
The key for me has been to “embrace the change”. I have come from a traditional DBA background, backups, consistency checks, server level configuration at the heart of things. Yes, I no longer care about SQL backups and things of that nature when operating within Azure but I have different tasks and to think about.
Sceptical? Please read on.
Do read on.
The Challenge: I am going to write about a way to move from Azure SQL Database (Platform as a service) back to a local SQL Server. I did encounter errors on the way but more importantly I have written how to avoid/solve them.
Another key point I made sure that there were no connections to the database when doing the below as I didn’t want in-flight data movement whilst doing it. If you can’t do this, then you should create a copy of the database and work from that.
It’s not a trivial operation, but Arun does walk us through the steps.
Let’s assume that you are not driven by logins, workers and session counts how does one select the right level? What exactly does DTUs (Database Transaction Units) mean? I suggest reading this post by Andy Mallon https://sqlperformance.com/2017/03/azure/what-the-heck-is-a-dtu
I am going to undersize my database and create a S0 database and run some day to day tasks – let’s see what happens. I will open up connections and issue some queries via my application. I would not class these queries as bad, what I am trying to drive here is getting the sizing right for your workload.
This is one of the trickier things to get, I think. We’re taking an existing workload and want to make sure it doesn’t fall over…but we aren’t measuring in terms of DTUs locally. I know that there are some tools that help the conversion process, but if you’re starting a new product or don’t have a great handle on normal workload, it’s really easy to fall into the Scylla and Charybdis of undersizing and overpaying.