29.12.11.11 The replication_connection_status Table

This table shows the current status of the I/O thread that handles the replica's connection to the source, information on the last transaction queued in the relay log, and information on the transaction currently being queued in the relay log.

Compared to the replication_connection_configuration table, replication_connection_status changes more frequently. It contains values that change during the connection, whereas replication_connection_configuration contains values which define how the replica connects to the source and that remain constant during the connection.

The replication_connection_status 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.

• GROUP_NAME

  If this server is a member of a group, shows the name of the group the server belongs to.

• SOURCE_UUID

  The server_uuid value from the source.

• THREAD_ID

  The I/O thread ID.

• SERVICE_STATE

  ON (thread exists and is active or idle), OFF (thread no longer exists), or CONNECTING (thread exists and is connecting to the source).

• RECEIVED_TRANSACTION_SET

  The set of global transaction IDs (GTIDs) corresponding to all transactions received by this replica. Empty if GTIDs are not in use. See GTID Sets for more information.

• LAST_ERROR_NUMBER, LAST_ERROR_MESSAGE

  The error number and error message of the most recent error that caused the I/O 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 MASTER or RESET REPLICA resets the values shown in these columns.

• LAST_ERROR_TIMESTAMP

  A timestamp in 'YYYY-MM-DD hh:mm:ss[.fraction]' format that shows when the most recent I/O error took place.

• LAST_HEARTBEAT_TIMESTAMP

  A timestamp in 'YYYY-MM-DD hh:mm:ss[.fraction]' format that shows when the most recent heartbeat signal was received by a replica.

• COUNT_RECEIVED_HEARTBEATS

  The total number of heartbeat signals that a replica received since the last time it was restarted or reset, or a CHANGE REPLICATION SOURCE TO | CHANGE MASTER TO statement was issued.

• LAST_QUEUED_TRANSACTION

  The global transaction ID (GTID) of the last transaction that was queued to the relay log.

• LAST_QUEUED_TRANSACTION_ORIGINAL_COMMIT_TIMESTAMP

  A timestamp in 'YYYY-MM-DD hh:mm:ss[.fraction]' format that shows when the last transaction queued in the relay log was committed on the original source.

• LAST_QUEUED_TRANSACTION_IMMEDIATE_COMMIT_TIMESTAMP

  A timestamp in 'YYYY-MM-DD hh:mm:ss[.fraction]' format that shows when the last transaction queued in the relay log was committed on the immediate source.

• LAST_QUEUED_TRANSACTION_START_QUEUE_TIMESTAMP

  A timestamp in 'YYYY-MM-DD hh:mm:ss[.fraction]' format that shows when the last transaction was placed in the relay log queue by this I/O thread.

• LAST_QUEUED_TRANSACTION_END_QUEUE_TIMESTAMP

  A timestamp in 'YYYY-MM-DD hh:mm:ss[.fraction]' format that shows when the last transaction was queued to the relay log files.

• QUEUEING_TRANSACTION

  The global transaction ID (GTID) of the currently queueing transaction in the relay log.

• QUEUEING_TRANSACTION_ORIGINAL_COMMIT_TIMESTAMP

  A timestamp in 'YYYY-MM-DD hh:mm:ss[.fraction]' format that shows when the currently queueing transaction was committed on the original source.

• QUEUEING_TRANSACTION_IMMEDIATE_COMMIT_TIMESTAMP

  A timestamp in 'YYYY-MM-DD hh:mm:ss[.fraction]' format that shows when the currently queueing transaction was committed on the immediate source.

• QUEUEING_TRANSACTION_START_QUEUE_TIMESTAMP

  A timestamp in 'YYYY-MM-DD hh:mm:ss[.fraction]' format that shows when the first event of the currently queueing transaction was written to the relay log by this I/O thread.

When the Performance Schema is disabled, local timing information is not collected, so the fields showing the start and end timestamps for queued transactions are zero.

The replication_connection_status table has these indexes:

• Primary key on (CHANNEL_NAME)

• Index on (THREAD_ID)

The following table shows the correspondence between replication_connection_status columns and SHOW REPLICA STATUS columns.

replication_connection_status Column	SHOW REPLICA STATUS Column
SOURCE_UUID	Master_UUID
THREAD_ID	None
SERVICE_STATE	Replica_IO_Running
RECEIVED_TRANSACTION_SET	Retrieved_Gtid_Set
LAST_ERROR_NUMBER	Last_IO_Errno
LAST_ERROR_MESSAGE	Last_IO_Error
LAST_ERROR_TIMESTAMP	Last_IO_Error_Timestamp