Patching SQL Azure
The Microsoft SQL Azure team is responsible for patching SQL Azure. that is to say, you do not need to download, install, or worry about the availability of your data during patching. A SQL Server DBA usually has concerns when updating SQL Server, usually around successful installation and post installation data accessibility.
However, SQL Azure is a completely fail-tolerant system designed to allow for rolling updates without interruption to the service. This means that when the updates are applied there is no interruption in your ability to access your data.
Operating System Patches
Operating system updates are updates to the underlying Windows operating system. They are the same as the operating system updates issued by Microsoft worldwide via Windows/Microsoft Update. Moreover, we regularly deploy operating system updates. Critical updates are given the highest priority and are deployed immediately.
Service Updates
Service updates are patches, enhancements and bugs fixes applied directly to the SQL Azure platform running on top of Windows. Moreover, service updates enhance and provide additional features to the SQL Azure platform.
Data Loss from Updates
- Firstly, there is no risk for data or schema loss for either service updates or operating system updates.
- Secondly, long before updates are deployed into production, our dedicated testing team extensively tests the updates and their deployment. And, there are many dedicated testing clusters and many servers to test deploy our service release.
- Thirdly, SQL Azure is designed to keep your data accessible across many different kinds of downtime events like hardware failures and power loss.
- Further, SQL Azure always keeps three replicas running to protect your data in the event of a failover (a primary replica and two secondary replicas). However, when a rolling update happens, we signal all the replicas on the server that we want to update to failover to other servers in the datacenter.
- However, one of the great things about SQL Azure is we maintain our failover capabilities during updates and this is provided to as part of the service
Transact-SQL
Service updates only add features to Transact SQL. This means if your transact-SQL is working on SQL Azure currently, it will continue to work after a service update. Additional features, syntaxes and semantics could be added to the language on a service update. However, none of these will affect the execution of your stored procedures or currently running queries. In other words, we will not break you code with a service update.
Reference: Microsoft Documentation