Channel based replication thread conflicts with Default Channel.

[Jesse Toninger]

Hi All,

I am trying to set up a multi-channel replication with 2 Masters feeding one Slave.

If I manually start each channel using 'Start slave for channel 'slave1/2'; everything is fine.

But if the server reboots, or I just issue a normal "START SLAVE;' command, it seems like the original default channel still tries to launch. This then causes a conflict where either itself or one of the channel threads will error out.

SELECT * FROM replication_connection_status\G;
*************************** 1. row ***************************
CHANNEL_NAME:
GROUP_NAME:
SOURCE_UUID: 7382909c-e2ad-11e8-950f-000c2929361a
THREAD_ID: NULL
SERVICE_STATE: OFF
COUNT_RECEIVED_HEARTBEATS: 17
LAST_HEARTBEAT_TIMESTAMP: 2018-11-13 16:01:50.684358
RECEIVED_TRANSACTION_SET: 7382909c-e2ad-11e8-950f-000c2929361a:1-4
LAST_ERROR_NUMBER: 13114
LAST_ERROR_MESSAGE: Got fatal error 1236 from master when reading data from binary log: 'A slave with the same server_uuid/server_id as this slave has connected to the master; the first event '' at 4, the last event read from '/var/log/mysql/mysql-bin.000004' at 41461, the last byte read from '/var/log/mysql/mysql-bin.000004' at 41461.'
LAST_ERROR_TIMESTAMP: 2018-11-13 16:01:50.781611
LAST_QUEUED_TRANSACTION:
LAST_QUEUED_TRANSACTION_ORIGINAL_COMMIT_TIMESTAMP: 0000-00-00 00:00:00.000000
LAST_QUEUED_TRANSACTION_IMMEDIATE_COMMIT_TIMESTAMP: 0000-00-00 00:00:00.000000
LAST_QUEUED_TRANSACTION_START_QUEUE_TIMESTAMP: 0000-00-00 00:00:00.000000
LAST_QUEUED_TRANSACTION_END_QUEUE_TIMESTAMP: 0000-00-00 00:00:00.000000
QUEUEING_TRANSACTION:
QUEUEING_TRANSACTION_ORIGINAL_COMMIT_TIMESTAMP: 0000-00-00 00:00:00.000000
QUEUEING_TRANSACTION_IMMEDIATE_COMMIT_TIMESTAMP: 0000-00-00 00:00:00.000000
QUEUEING_TRANSACTION_START_QUEUE_TIMESTAMP: 0000-00-00 00:00:00.000000
*************************** 2. row ***************************
CHANNEL_NAME: sc-1
GROUP_NAME:
SOURCE_UUID: 7382909c-e2ad-11e8-950f-000c2929361a
THREAD_ID: 57
SERVICE_STATE: ON
COUNT_RECEIVED_HEARTBEATS: 5623
LAST_HEARTBEAT_TIMESTAMP: 2018-11-15 14:52:52.402809
RECEIVED_TRANSACTION_SET:
LAST_ERROR_NUMBER: 0
LAST_ERROR_MESSAGE:
LAST_ERROR_TIMESTAMP: 0000-00-00 00:00:00.000000
LAST_QUEUED_TRANSACTION:
LAST_QUEUED_TRANSACTION_ORIGINAL_COMMIT_TIMESTAMP: 0000-00-00 00:00:00.000000
LAST_QUEUED_TRANSACTION_IMMEDIATE_COMMIT_TIMESTAMP: 0000-00-00 00:00:00.000000
LAST_QUEUED_TRANSACTION_START_QUEUE_TIMESTAMP: 0000-00-00 00:00:00.000000
LAST_QUEUED_TRANSACTION_END_QUEUE_TIMESTAMP: 0000-00-00 00:00:00.000000
QUEUEING_TRANSACTION:
QUEUEING_TRANSACTION_ORIGINAL_COMMIT_TIMESTAMP: 0000-00-00 00:00:00.000000
QUEUEING_TRANSACTION_IMMEDIATE_COMMIT_TIMESTAMP: 0000-00-00 00:00:00.000000
QUEUEING_TRANSACTION_START_QUEUE_TIMESTAMP: 0000-00-00 00:00:00.000000
*************************** 3. row ***************************
CHANNEL_NAME: sc-2
GROUP_NAME:
SOURCE_UUID: c5b263d8-e433-11e8-8c4f-5254009262e2
THREAD_ID: 59
SERVICE_STATE: ON
COUNT_RECEIVED_HEARTBEATS: 5623
LAST_HEARTBEAT_TIMESTAMP: 2018-11-15 14:52:51.955988
RECEIVED_TRANSACTION_SET:
LAST_ERROR_NUMBER: 0
LAST_ERROR_MESSAGE:
LAST_ERROR_TIMESTAMP: 0000-00-00 00:00:00.000000
LAST_QUEUED_TRANSACTION:
LAST_QUEUED_TRANSACTION_ORIGINAL_COMMIT_TIMESTAMP: 0000-00-00 00:00:00.000000
LAST_QUEUED_TRANSACTION_IMMEDIATE_COMMIT_TIMESTAMP: 0000-00-00 00:00:00.000000
LAST_QUEUED_TRANSACTION_START_QUEUE_TIMESTAMP: 0000-00-00 00:00:00.000000
LAST_QUEUED_TRANSACTION_END_QUEUE_TIMESTAMP: 0000-00-00 00:00:00.000000
QUEUEING_TRANSACTION:
QUEUEING_TRANSACTION_ORIGINAL_COMMIT_TIMESTAMP: 0000-00-00 00:00:00.000000
QUEUEING_TRANSACTION_IMMEDIATE_COMMIT_TIMESTAMP: 0000-00-00 00:00:00.000000
QUEUEING_TRANSACTION_START_QUEUE_TIMESTAMP: 0000-00-00 00:00:00.000000
--------------------------

There is no Channel name, but the thread still tried to start and fails.

How can I remove or disable the default thread from running when the server reboots? Or is there another step I am missing here?

Thanks!