MySQL 9.0 Reference Manual Including MySQL NDB Cluster 9.0
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
replica_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
REPLICA statement, the columns beginning
APPLYING_TRANSACTION are reset.
The
replication_applier_status_by_worker
table has these columns:
CHANNEL_NAME
The replication channel which this row is displaying. There is always a default replication channel, and more replication channels can be added. See Section 19.2.2, “Replication Channels” for more information.
WORKER_ID
The worker identifier (same value as the
id column in the
mysql.slave_worker_info table). After
STOP
REPLICA, the THREAD_ID column
becomes NULL, but the
WORKER_ID value is preserved.
THREAD_ID
The worker thread ID.
SERVICE_STATE
ON (thread exists and is active or
idle) or OFF (thread no longer exists).
LAST_ERROR_NUMBER,
LAST_ERROR_MESSAGE
The error number and error message of the most recent
error that caused the worker thread to stop. An error
number of 0 and message of the empty string mean “no
error”. If the
LAST_ERROR_MESSAGE value is not empty,
the error values also appear in the replica's error log.
Issuing RESET BINARY LOGS AND
GTIDS or
RESET
REPLICA resets the values shown in these
columns.
LAST_ERROR_TIMESTAMP
A timestamp in '
format that shows when the most recent worker error
occurred.
YYYY-MM-DD
hh:mm:ss[.fraction]'
LAST_APPLIED_TRANSACTION
The global transaction ID (GTID) of the last transaction applied by this worker.
LAST_APPLIED_TRANSACTION_ORIGINAL_COMMIT_TIMESTAMP
A timestamp in '
format that shows when the last transaction applied by
this worker was committed on the original source.
YYYY-MM-DD
hh:mm:ss[.fraction]'
LAST_APPLIED_TRANSACTION_IMMEDIATE_COMMIT_TIMESTAMP
A timestamp in '
format that shows when the last transaction applied by
this worker was committed on the immediate source.
YYYY-MM-DD
hh:mm:ss[.fraction]'
LAST_APPLIED_TRANSACTION_START_APPLY_TIMESTAMP
A timestamp in '
format that shows when this worker started applying the
last applied transaction.
YYYY-MM-DD
hh:mm:ss[.fraction]'
LAST_APPLIED_TRANSACTION_END_APPLY_TIMESTAMP
A timestamp in '
format that shows when this worker finished applying the
last applied transaction.
YYYY-MM-DD
hh:mm:ss[.fraction]'
APPLYING_TRANSACTION
The global transaction ID (GTID) of the transaction this worker is currently applying.
APPLYING_TRANSACTION_ORIGINAL_COMMIT_TIMESTAMP
A timestamp in '
format that shows when the transaction this worker is
currently applying was committed on the original source.
YYYY-MM-DD
hh:mm:ss[.fraction]'
APPLYING_TRANSACTION_IMMEDIATE_COMMIT_TIMESTAMP
A timestamp in '
format that shows when the transaction this worker is
currently applying was committed on the immediate source.
YYYY-MM-DD
hh:mm:ss[.fraction]'
APPLYING_TRANSACTION_START_APPLY_TIMESTAMP
A timestamp in '
format that shows when this worker started its first
attempt to apply the transaction that is currently being
applied.
YYYY-MM-DD
hh:mm:ss[.fraction]'
LAST_APPLIED_TRANSACTION_RETRIES_COUNT
The number of times the last applied transaction was retried by the worker after the first attempt. If the transaction was applied at the first attempt, this number is zero.
LAST_APPLIED_TRANSACTION_LAST_TRANSIENT_ERROR_NUMBER
The error number of the last transient error that caused the transaction to be retried.
LAST_APPLIED_TRANSACTION_LAST_TRANSIENT_ERROR_MESSAGE
The message text for the last transient error that caused the transaction to be retried.
LAST_APPLIED_TRANSACTION_LAST_TRANSIENT_ERROR_TIMESTAMP
A timestamp in '
format for the last transient error that caused the
transaction to be retried.
YYYY-MM-DD
hh:mm:ss[.fraction]'
APPLYING_TRANSACTION_RETRIES_COUNT
The number of times the transaction that is currently being applied was retried until this moment. If the transaction was applied at the first attempt, this number is zero.
APPLYING_TRANSACTION_LAST_TRANSIENT_ERROR_NUMBER
The error number of the last transient error that caused the current transaction to be retried.
APPLYING_TRANSACTION_LAST_TRANSIENT_ERROR_MESSAGE
The message text for the last transient error that caused the current transaction to be retried.
APPLYING_TRANSACTION_LAST_TRANSIENT_ERROR_TIMESTAMP
A timestamp in '
format for the last transient error that caused the
current transaction to be retried.
YYYY-MM-DD
hh:mm:ss[.fraction]'
The
replication_applier_status_by_worker
table has these indexes:
Primary key on (CHANNEL_NAME,
WORKER_ID)
Index on (THREAD_ID)
The following table shows the correspondence between
replication_applier_status_by_worker
columns and
SHOW
REPLICA STATUS columns.
replication_applier_status_by_worker Column |
SHOW REPLICA 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 |