MySQL raises error 3074 when a replication statement references a channel name that is not configured on the server.
MySQL error 3074 ER_SLAVE_CHANNEL_DOES_NOT_EXIST occurs when a START SLAVE, STOP SLAVE, or CHANGE MASTER TO command refers to a replication channel that the server does not know. Create the channel with CHANGE MASTER TO FOR CHANNEL or correct the name to fix the problem.
ER_SLAVE_CHANNEL_DOES_NOT_EXIST
MySQL returns error 3074 when a replication statement references a channel that the server has no record of. The message displayed is Slave channel '%s' does not exist, where %s is the requested channel.
The error was introduced in MySQL 5.7.6 together with multi source replication. It is triggered by START SLAVE, STOP SLAVE, CHANGE MASTER TO, RESET SLAVE, or SHOW SLAVE STATUS FOR CHANNEL commands. Replication for that channel will not start until the definition exists, so the issue must be resolved quickly.
Most often a misspelled channel name triggers the error. If you type prod_chanel instead of prod_channel, MySQL cannot find matching metadata and raises 3074.
The error also appears when the channel was never created with CHANGE MASTER TO FOR CHANNEL or was removed by RESET SLAVE ALL but scripts still reference it.
Cloning or restoring a replica from backup can wipe channel definitions. Any automation that starts replication afterwards fails with 3074.
First, list existing channels to confirm what the server recognizes.
SHOW ALL SLAVES STATUS;
If the intended channel is absent, create it with CHANGE MASTER TO FOR CHANNEL.
CHANGE MASTER TO SOURCE_HOST='primary', SOURCE_PORT=3306, SOURCE_USER='repl', SOURCE_PASSWORD='secret', SOURCE_LOG_FILE='binlog.000123', SOURCE_LOG_POS=456 FOR CHANNEL 'prod_channel';
Then start replication for that channel.
START SLAVE FOR CHANNEL 'prod_channel';
If the name was only mistyped, reissue the command using the correct channel identifier.
During automated failover, orchestration scripts sometimes stop or start a channel that was never provisioned. Add a guard clause that checks performance_schema.replication_applier_status_by_channel before issuing replication commands.
When upgrading from single source to multi source replication, existing scripts may omit FOR CHANNEL clauses. Add them or drop the clause for default channels to avoid confusion.
Standardize channel names across environments and store them as constants in configuration management.
Version control CHANGE MASTER statements with schema migrations so rebuilding a replica always recreates every required channel.
Include automated tests that verify expected channels after provisioning by querying performance_schema tables.
Monitoring tools like Galaxy alert immediately when START SLAVE fails, letting teams correct channel names before replication lag grows.
ER_SLAVE_CHANNEL_NAME_INVALID (3075) arises when the channel name exceeds 63 characters or starts with a digit. Shorten the name to resolve.
ER_SLAVE_MULTIPLE_CHANNELS_HOST_PORT (3070) indicates two channels share the same source host and port. Update one configuration to eliminate the conflict.
ER_CHANNELS_REQUIRE_BOTH_ENGINE_AND_SOURCE (3080) surfaces if SOURCE_ENGINE is omitted while defining a channel in multi source setups. Supply both parameters.
A typo in the FOR CHANNEL clause or START SLAVE statement prevents MySQL from matching the requested channel.
An administrator references a channel that was not previously defined with CHANGE MASTER TO FOR CHANNEL.
A cleanup script runs RESET SLAVE ALL, deleting every channel, but other automation still tries to start them.
Backups taken before channels were configured produce replicas without the required channel definitions.
Channel names differ between staging and production, causing deployment scripts to fail when run in the wrong environment.
Channel name violates length or character rules.
Two channels share identical source host and port.
Missing SOURCE_ENGINE parameter when defining a channel.
Attempting to create a channel that already exists.
Run SHOW SLAVE STATUS or query performance_schema.replication_applier_status_by_channel to list configured channels.
MySQL does not support renaming. Create a new channel, synchronize it, then drop the old one.
No. Multi source replication and channel concepts were added in 5.7.6, so MySQL 5.6 never raises error 3074.
Galaxy highlights failed replication statements and lets teams share vetted CHANGE MASTER scripts, preventing typos.
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