Accelerated Database Recovery (ADR)

Accelerated Database Recovery, or ADR, is a new database recovery option that greatly increases the availability and decreases the time in scenarios such as crash recovery (database recovery in the event of a server/database crash), Always On availability group failover, and long-running transaction rollback (for example, a large bulk insert or an index rebuild rollback).

A SQL database consists of data and a transaction log file. A data file contains the table data. A transaction log file keeps track of all the changes made to the data and the schema; for example, if there is an insert in a table, the transaction log file contains the insert statement and whether the insert statement was committed or not.

To better understand ADR, let's first get an understanding of the current database recovery process.

Figure 8.4: The recovery phase without ADR

Note

Image taken from https://docs.microsoft.com/en-us/azure/sql-database/sql-database-accelerated...