What's New in Windows Azure SQL Database (formerly SQL Azure)

Windows Azure SQL Database November 2012 release offers several enhancements. These enhancements include:

• Updates to Throttling Behavior:
  
  Starting with this release, soft throttling on worker threads is changing. Over the next few months, soft throttling will eventually be replaced by worker thread governance. In the meantime, users may see requests failing due throttling on worker threads (error 40501) or worker thread governance (errors 10928 and 10929). The retry logic in your application should be modified to handle these errors. Please see http://go.microsoft.com/fwlink/?LinkId=267637 for more information on this topic.
  
  
• New Event Table for Troubleshooting:
  
  To assist in tracking and troubleshooting database activity, a new set of system views have been added to the logical master database. These views record database connectivity-related events, including successful, failed, and terminated connections; throttling; and deadlocks. Summary statistics are available in the new view sys.database_connection_stats and aggregated details are available in sys.event_log. For more information on using these tables, see SQL Server Connectivity Event Tables in Troubleshooting Windows Azure SQL Database. For information on viewing these events in the management portal, see Track Database Events in Database Administration (Management Portal for SQL Database).
  
  
• SQL Server can reference a SQL Database (except the virtual master database) as the target of linked servers and distributed queries.
  
  
• Recursive triggers are supported.
  
  
• DBCC SHOW_STATISTICS is supported.
  
  

Windows Azure SQL Database November 2011 release offers several enhancements. These enhancements include:

• Federations in SQL Database: SQL Database now provides the ability to scale your data through horizontal partitioning. Federations can be used to dynamically scale your database to achieve greater performance and capacity without any downtime. For more information, see Federations in Windows Azure SQL Database (formerly SQL Azure).
  
  
  
  
• Increased Database Size: SQL Database Business Edition now supports databases up to 150 GB.
  
  
  
  
• Refreshed SQL Database Management Portal:
  
  The new portal has significant new features, including:
  
  
  • New workspaces to more easily monitor databases.
    
    
  • Drill-down into schemas, query plans, spatial data, and indexes/keys.
    
    
  • New query performance statistics.
    
    
  • Manage your database schema changes through DAC upgrades.
    
    
  • Support for SQL Database Federations.
    
    
• Click the following link to read about how to Get started with the Management Portal for Windows Azure SQL Database.
  
  
• Updated Import/Export Service: The service has been updated to address several issues since its initial release in the last SQL Database update. You can continue using this free service to import and export data between SQL Database and Windows Azure BLOB storage. More information, including a sample implementation is available on the sample CodePlex page.
  
  
  
  
• Expanded Support for User-Controlled Collations: When creating a database, you can now specify which collation to use. You can specify all valid collations returned from the fn_helpcollations() system function. This function is now enabled in SQL Database. By default, temporary data will have the same collation as the database it is created in. Databases created as a result of the copy operation will inherit the collation from the source database. For more information, see CREATE DATABASE (Windows Azure SQL Database).
  
  
  
  
• Updated Engine Version: This release updates the underlying SQL Database engine version from 11.0.1477.26 to 11.0.1750.34 as it is rolled out across data centers.
  
  You will see this server version number change in server-side APIs such as SERVERPROPERTY('ProductVersion') and @@VERSION; and also in client-side APIs such as ODBC: SQLGetInfo (SQL_DBMS_VER) and SqlClient: SqlConnection.ServerVersion.
  
  
  
  
• Updates to Throttling Behavior:
  
  
  • What has changed recently with respect to throttling?
    
    An improvement was deployed in September 2011 to disable CPU usage based throttling, by enabling the SQL Server Resource Governor. Historically, CPU throttling has accounted for a large proportion of all throttling events.
    
    
  • What will be changed when Q4SR is deployed?
    
    Multi-tenancy has been improved by dividing user and system workloads into multiple resource pools. Pools for critical tasks have guaranteed CPU resources to increase availability.
    
    
  • What hasn’t changed?
    
    CPU triggered throttling is still disabled;
    
    Throttling due to other resource types still exists and there has been no change to these conditions. For more information, see Windows Azure SQL Database Engine Throttling Reference.
    
    
  • What is the potential impact?
    
    If a system becomes busy and there is contention for CPU, user requests will be allocated fewer CPU cycles instead of being disconnected. This would be experienced as slower response until demand reduces, or load balancing is engaged.
    
    Applications that are expecting dropped connections and have a dependency on explicit throttling errors (CPU and others) may need to account for slower response times instead.
    
    

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