Error 3078 ER_SLAVE_CHANNEL_DELETE is raised when MySQL cannot remove replication metadata for a channel because replication threads are still running or the user lacks the required privileges.
MySQL Error 3078 ER_SLAVE_CHANNEL_DELETE appears when the server cannot delete replication metadata for a channel, usually because the channel is still running or you lack SUPER or REPLICATION SLAVE ADMIN rights. Stop the channel and retry RESET SLAVE or CHANGE REPLICATION SOURCE TO to resolve the issue.
ER_SLAVE_CHANNEL_DELETE
MySQL raises error 3078 (SQLSTATE HY000) with the condition name ER_SLAVE_CHANNEL_DELETE when the server fails to delete internal replication metadata for a specific replication channel.
The error message appears during RESET SLAVE, CHANGE REPLICATION SOURCE TO, or DROP CHANNEL operations. It indicates that slave info tables or files could not be removed, leaving the channel in an inconsistent state.
The error occurs in MySQL 5.7.6 and later whenever replication metadata must be purged, but active replication threads, open transactions, or insufficient permissions block the operation.
Administrators typically see the message while cleaning up multi-source replication channels or reconfiguring replication topology.
Failure to delete stale metadata prevents channel recreation, blocks replication restarts, and risks data drift between source and replica. Prompt resolution avoids replication downtime.
Active io_thread or sql_thread keeps metadata locked, so deletion fails.
Running transactions referencing the channel hold metadata until commit or rollback, blocking deletion.
Missing SUPER or REPLICATION SLAVE ADMIN privileges stop metadata operations.
File system permission issues prevent removal of relay-log or metadata files.
Internal bugs in earlier 5.7 releases occasionally leave orphaned rows in mysql.slave_master_info and slave_relay_log_info tables.
Stop replication threads on the affected channel before retrying RESET SLAVE.
Ensure the current user holds SUPER or REPLICATION SLAVE ADMIN as well as FILE privileges.
Commit or roll back open transactions on the replica that reference the channel.
If files remain, remove them manually and run FLUSH RELAY LOGS.
During topology migration, first issue STOP REPLICA FOR CHANNEL 'channel_A'; then RESET REPLICA ALL FOR CHANNEL 'channel_A'; to delete metadata safely.
When privilege issues cause the error, grant REPLICATION SLAVE ADMIN ON *.* TO 'admin'@'%'; and rerun the metadata command.
After an unclean shutdown, orphaned metadata rows can be removed with DELETE FROM mysql.slave_master_info WHERE channel_name='channel_A'; followed by a server restart.
Always stop replication threads before modifying or dropping replication channels.
Use dedicated administration accounts with correct replication privileges.
Automate health checks that verify no threads run before cleanup scripts execute.
Upgrade to the latest MySQL minor version to benefit from bug fixes in replication metadata handling.
Error 1872 ER_SLAVE_CHANNEL_CREATE: triggered when creating a duplicate channel.
Error 3084 ER_SLAVE_CHANNEL_NAME_INVALID_OR_TOO_LONG: occurs when the channel name does not meet length constraints.
Error 1201 HY000 Master and Slave have equal MySQL server UUIDs: happens when source and replica share the same server_uuid.
io_thread or sql_thread running on the channel keeps metadata locked.
Long-running transactions referencing the channel delay metadata deletion.
Lack of SUPER or REPLICATION SLAVE ADMIN blocks RESET SLAVE.
OS user cannot remove relay-log or metadata files.
Previous crashes left rows in mysql.slave_master_info or slave_relay_log_info.
Raised when attempting to create a channel that already exists. Stop and drop the existing channel before retrying.
Occurs when the channel name exceeds 64 characters or contains invalid characters. Use shorter, alphanumeric names.
Happens when the replica is cloned from the source without changing server_uuid.
Run SHOW REPLICA STATUS FOR CHANNEL 'channel_A'G and review Slave_IO_Running and Slave_SQL_Running.
Manual file deletion works only after stopping replication and should be followed by RESET REPLICA to refresh metadata.
SUPER or REPLICATION SLAVE ADMIN plus FILE privilege are needed to remove replication metadata.
Galaxy surfaces privilege errors inline and lets administrators share corrected scripts with proper credentials.
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