04Mar 2019 by Grant Fritchey 4 Comments

system_health Extended Events in Azure SQL Database

Azure, SQL Server
The system_health Extended Events session is incredibly useful. Further, it's running, by default, in every server you have under management that is 2008 or greater. Things are not the same in Azure though. system_health in Azure SQL Database If you look at the documentation for system_health, it shows that it's applicable to Azure SQL Database. However, if you try to run the example query, it won't work. This is because the implementation of Extended Events inside Azure SQL Database is a little different. Instead, you need to use the Azure SQL Database equivalent system views to create the same query like this: SELECT CAST(dxdst.target_data AS XML) FROM sys.dm_xe_database_session_targets AS dxdst JOIN sys.dm_xe_database_sessions AS dxds ON dxds.address = dxdst.event_session_address WHERE dxds.name = 'system_health'; Now, running this in Azure, prepare to be…
Read More
08May 2017 by Grant Fritchey 9 Comments

General Notes on Security in Azure SQL Data Warehouse

Azure
I'm still learning about Azure SQL Data Warehouse (ADW, cause I'm lazy). ADW is a deceptively deep topic. Initially you think that it's just SQL Server, what's the big deal. Then you start to understand the underlying architecture and things get complicated. Then you begin to understand the implications of the architecture and things get down right arcane. However, I'd like to talk about some relatively easy concepts around security in your Azure SQL Data Warehouse. For lots more detail, see the excellent documentation provided by Microsoft. Firewall Security The single most important aspect of security in and around Azure is the fact that for the public facing aspects (and the database stuff is public facing), there is a built-in firewall. This firewall is enabled by default and actually can't…
Read More
18Jan 2017 by Grant Fritchey 7 Comments

Scheduling Statistics Maintenance in Azure SQL Data Warehouse

Azure
The power and capabilities of Azure SQL Data Warehouse are pretty amazing. However, it's still basically SQL Server under the covers. SQL Server still needs maintenance and one type of maintenance is keeping statistics up to date. Statistics maintenance is doubly important within Azure SQL Data Warehouse because statistics are not created automatically, nor are they maintained automatically. It's up to you to ensure your statistics are up to date. Statistics in Azure SQL Data Warehouse It's worth re-emphasizing the point that there is no automatic creation of statistics in Azure SQL Data Warehouse. This means you need to plan to add statistics to your tables. Microsoft recommends an easy method is to add them to every column. While that does make things easy, it's not like statistics are free. If you…
Read More
29Aug 2016 by Grant Fritchey 7 Comments

Azure SQL Data Warehouse Execution Plans

Azure
Azure SQL Data Warehouse can sometimes feel like it's completely different from SQL Server, but under the covers, it is still (mostly) SQL Server and it does have execution plans. Let's take a look at one. I've created a new SQL Data Warehouse using the sample database available on the portal, AdventureWorksDW. Here's a query against that database: SELECT dd.FullDateAlternateKey AS OrderDate, dc.LastName, SUM(fis.SalesAmount) AS SumSalesAmount FROM dbo.FactInternetSales AS fis JOIN dbo.DimDate AS dd ON fis.OrderDateKey = dd.DateKey JOIN dbo.DimCustomer AS dc ON dc.CustomerKey = fis.CustomerKey GROUP BY dd.FullDateAlternateKey, dc.LastName HAVING SUM(fis.SalesAmount) > 5000.0 ORDER BY OrderDate DESC; If I attempt to capture an execution plan using the SQL Server Management Studio GUI, nothing happens. If I try to use T-SQL commands, I get an error that those commands are…
Read More
15Feb 2016 by Grant Fritchey 11 Comments

Loading Data into Azure SQL Data Warehouse

Azure, Data Science
Ouch. Let's start with the level set. I'm not an ETL expert. In fact, I haven't done any professional ETL work for several years. My skills are, at best, rusty. With this in mind, I knew I'd have a hard time extracting data from a local database in order to move it up to Azure SQL Data Warehouse. I expected to be fumbling and slow and to constantly feel more than a little stupid as I made one mistake after another. All of this came to pass. Yet... OMG! THAT WAS DIFFICULT! Here's how I started. I defined a bcp command for the tables I was interested in. I ensured it was working correctly, then wrote a little PowerShell script so I could supply a list of tables and get…
Read More
03Dec 2015 by Grant Fritchey 4 Comments

Changing Course On Learning

Azure, Database Lifecycle Management, DevOps, DocumentDB, Professional Development
With all the new stuff on the Microsoft Data Platform, it's really hard to keep up with it all. I had announced my plans to charge down the DocumentDB road to try to get the basics of that in my head along with learning some JSON so I could get what all the hoopla is about. However, after a lot of thought and some extensive meetings at Redgate, I'm looking to shift my learning in a new direction. First up. Arrrrrrrrr! No, it's not yet "Talk Like a Pirate Day." I'm going to start learning the R language. It's a language for statistical computing and is one of the many underpinnings for what's going to be happening with a lot of the Machine Learning capabilities in the Data Platform. With Azure…
Read More