MySQL 8.0 Reference Manual Including MySQL NDB Cluster 8.0

26.12.11.6 The replication_applier_status_by_worker Table

This table provides details of the transactions handled by applier threads on a replica or Group Replication group member. For a single-threaded replica, data is shown for the replica's single applier thread. For a multithreaded replica, data is shown individually for each applier thread. The applier threads on a multithreaded replica are sometimes called workers. The number of applier threads on a replica or Group Replication group member is set by the slave_parallel_workers system variable, which is set to zero for a single-threaded replica. A multithreaded replica also has a coordinator thread to manage the applier threads, and the status of this thread is shown in the replication_applier_status_by_coordinator table.

All error codes and messages displayed in the columns relating to errors correspond to error values listed in Server Error Message Reference.

When the Performance Schema is disabled, local timing information is not collected, so the fields showing the start and end timestamps for applied transactions are zero. The start timestamps in this table refer to when the worker started applying the first event, and the end timestamps refer to when the last event of the transaction was applied.

When a replica is restarted by a START SLAVE statement, the columns beginning APPLYING_TRANSACTION are reset. Before MySQL 8.0.13, these columns were not reset on a replica that was operating in single-threaded mode, only on a multithreaded replica.

The replication_applier_status_by_worker table has these columns:

The replication_applier_status_by_worker table has these indexes:

The following table shows the correspondence between replication_applier_status_by_worker columns and SHOW SLAVE STATUS columns.

replication_applier_status_by_worker Column SHOW SLAVE STATUS Column
WORKER_ID None
THREAD_ID None
SERVICE_STATE None
LAST_ERROR_NUMBER Last_SQL_Errno
LAST_ERROR_MESSAGE Last_SQL_Error
LAST_ERROR_TIMESTAMP Last_SQL_Error_Timestamp