Tablespaces ALTER UNDO TABLESPACE  tablespace_name  SET ACTIVE; An undo tablespace in an  empty  state can also be dropped. See Dropping Undo Tablespaces. The purge thread is responsible for emptying and truncating undo tablespaces. By default, the purge thread looks for undo tablespaces to truncate once every 128 times that purge is invoked. The frequency with which the purge thread looks for undo tablespaces to truncate is controlled by the innodb_purge_rseg_truncate_frequency  variable, which has a default setting of 128. Expediting Automated Truncation of Undo Tablespaces To increase the frequency, decrease the  innodb_purge_rseg_truncate_frequency  setting. For example, to have the purge thread look for undo tabespaces once every 32 times that purge is invoked, set innodb_purge_rseg_truncate_frequency  to 32. When an undo tablespace is truncated, the rollback segments in the undo tablespace are deactivated. The active rollback segments in other undo tablespaces assume responsibility for the entire system load, which may result in a slight performance degradation. The extent to which performance is affected depends on a number of factors: Performance Impact of Truncating Undo Tablespace Files •Number of undo tablespaces •Number of undo logs •Undo tablespace size •Speed of the I/O susbsystem •Existing long running transactions •System load The easiest way to avoid the potential performance impact is to increase the number of undo tablespaces. As of MySQL 8.0.16,  undo  and  purge  susbsystem counters are provided for monitoring background activities associated with undo log truncation. For counter names and descriptions, query the INFORMATION_SCHEMA.INNODB_METRICS  table. SELECT NAME, SUBSYSTEM, COMMENT FROM INFORMATION_SCHEMA.INNODB_METRICS WHERE NAME LIKE ’%truncate%’; For information about enabling counters and querying counter data, see Section 15.15.6, “InnoDB INFORMATION_SCHEMA Metrics Table” . As of MySQL 8.0.21, the number of truncate operations on the same undo tablespace between checkpoints is limited to 64. The limit prevents potential issues caused by an excessive number of undo 3065 Undo Tablespace Truncation Limit Monitoring Undo Tablespace Truncation mysql>  SELECT @@innodb_purge_rseg_truncate_frequency; +----------------------------------------+ | @@innodb_purge_rseg_truncate_frequency | +----------------------------------------+ | 128 | +----------------------------------------+ mysql>  SET GLOBAL innodb_purge_rseg_truncate_frequency=32;