Taiob Ali gives us a briefing summary on Azure SQL Database Serverless:
Occasionally, load balancing automatically occurs if the machine cannot satisfy resource demand within a few minutes. For example, if the resource demand is 4 vCores, but only 2 vCores are available, it may take up to a few minutes to load balance before 4 vCores are provided. The database remains online during load balancing except for a brief period at the end of the operation when connections are dropped.
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