SQL Server conducts a forward scan of the transaction log from the beginning of the last successful checkpoint (or the oldest dirty page LSN) until the end, to determine the state of each transaction at the time SQL Server stopped. Without ADR, database recovery in SQL Server follows the ARIES recovery model and consists of three phases, which are illustrated in the following diagram and explained in more detail following the diagram. With ADR, the transaction log is aggressively truncated, even in the presence of active long running transactions, which prevents it from growing out of control. With ADR, transaction rollback is instantaneous, irrespective of the time that the transaction has been active or the number of updates that has performed. With ADR, long running transactions don't impact the overall recovery time, enabling fast and consistent database recovery irrespective of the number of active transactions in the system or their sizes. To work with ADR, review Manage accelerated database recovery. This article provides an overview of the ADR feature. For more about ADR in Azure SQL, see Accelerated Database Recovery in Azure SQL. ADR is enabled by default in SQL Database and SQL Managed Instance and can't be disabled. ADR is also available for databases in Azure SQL Database, Azure SQL Managed Instance, and Azure Synapse SQL. SQL Server 2019 (15.x) Azure SQL Database Azure SQL Managed Instance Azure Synapse AnalyticsĪccelerated database recovery (ADR) improves database availability, especially in the presence of long running transactions, by redesigning the SQL database engine recovery process.ĪDR was introduced in SQL Server 2019 (15.x) and improved in SQL Server 2022 (16.x).
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