An amazing blog post by Microsoft describing the idea of hot patching the database engine in Azure SQL Database to allow for minimal downtime when applying patches to SQL Server. We know that it is one of the benefits of Azure SQL Database but now we get some insight into how it’s done.

I always wanted to know how this was done, I always had a feeling that database failover was not enough. Grab a coffee and enjoy the read – a line from the last paragraph grabbed my attention – “but some day it may also come to SQL Server.”

https://techcommunity.microsoft.com/t5/Azure-SQL-Database/Hot-Patching-SQL-Server-Engine-in-Azure-SQL-Database/ba-p/849700