Rollback Parameters

max_undo_workers

Parameter description: Specifies the number of undo worker threads called during asynchronous rollback. The parameter setting takes effect after the system is restarted.

Parameter type: integer

Unit: none

Value range: 1 to 100

Default value: 5

Setting method: This is a POSTMASTER parameter. Set it based on instructions provided in Table 1.

Setting suggestion: Retain the default value.

Risks and impacts of improper settings: Only the maximum number of threads that can concurrently perform asynchronous rollback is affected. If the value is too small, the asynchronous rollback speed may be slow. When a large number of transactions that require asynchronous rollback exist in the system, there is an extremely low probability that the undo reclamation speed is affected. If the host configuration is not high and a large number of transactions that require asynchronous rollback exist in the system, a large number of asynchronous rollback threads will be started at the same time, occupying certain system resources.