ADR cleaner retry timeout (min) configuration option

Applies to: yesSQL Server (all supported versions)

Introduced in SQL Server 2019.

This configuration setting is required for accelerated database recovery. The cleaner is the asynchronous process that wakes up periodically and cleans page versions that are not needed.

Occasionally the cleaner runs into issues while acquiring object level locks due to conflicts with user workload during its sweep. It tracks such pages in a separate list. The ADR cleaner retry timeout (default value of 15) controls the amount of time the cleaner would spend exclusively retrying object lock acquisition and cleanup of page before abandoning the sweep. Completion of a sweep with 100% success is essential to keep the growth of aborted transactions in the aborted transactions map. If the separate list cannot be cleaned up in the prescribed timeout, then the current sweep will be abandoned and the next sweep will start.

Remarks

The cleaner is single threaded in SQL Server 2019 and so one SQL Server instance can work on one database at a time. If the instance has more than one user database with ADR enabled, then do not increase the timeout to a large value as that could delay cleanup on one database while the retry is happening on another database.

Examples

The following examples sets the cleaner retry timeout.

sp_configure 'show advanced options', 1;  
RECONFIGURE;
GO 
sp_configure 'ADR cleaner retry timeout', 15;  
RECONFIGURE;  
GO  

See Also