Topic Status: Some information in this topic is preview and subject to change in future releases. Preview information describes new features or changes to existing features in Microsoft SQL Server 2016 Community Technology Preview 2 (CTP2).
Flushes to disk the transaction log of the current database, thereby hardening all previously committed delayed durable transactions.
If you choose to use delayed transaction durability because of the performance benefits, but you also want to have a guaranteed limit on the amount of data that is lost on server crash or failover, then execute sys.sp_flush_log on a regular schedule. For example, if you want to make sure you don’t lose more than x seconds worth of data, you would execute sp_flush_log every x seconds.
Applies to: SQL Server (SQL Server 2016 through current version).
Executing sys.sp_flush_log guarantees that all previously committed delayed durable transactions are made durable. See the conceptual topic Control Transaction Durability for more information.