Error 3083 indicates that a START SLAVE or START REPLICA command was issued for a replication channel that is already running.
ER_SLAVE_CHANNEL_WAS_RUNNING occurs when you try to start replication on a channel that is already active. Verify channel status with SHOW SLAVE STATUS and skip START SLAVE if Slave_IO_State is not "Stopped" to resolve the error.
ER_SLAVE_CHANNEL_WAS_RUNNING
Error 3083 appears when a START SLAVE or START REPLICA command targets a replication channel that MySQL already considers active. The server prevents duplicate thread creation to protect replication integrity.
The error was introduced in MySQL 5.7.6 and later persists through 8.4. It is reported as SQLSTATE HY000, signaling a general runtime issue.
DBAs meet this error after automated failover scripts, scheduled jobs, or manual commands attempt to start replication without checking the current Slave_IO_State or Slave_SQL_Running status.
It often arises in multi-source replication where each channel is managed independently. Over-eager orchestration tools that loop over channels can trigger redundant START statements.
Although replication keeps running, repeated failed START statements clutter logs, hide real issues, and may block automation flows that expect success status codes.
Cleaning up the workflow prevents alert fatigue, ensures idempotent automation, and guards against race conditions during planned failover or promotion.
The primary cause is issuing START SLAVE on a channel whose Slave_IO_Running and Slave_SQL_Running are both Yes. MySQL raises Error 3083 to indicate no action is required.
Misconfigured monitoring tools, double-executed initialization scripts, or operators unaware of multi-channel state frequently trigger the problem.
First, confirm the channel state using:
SHOW SLAVE STATUS FOR CHANNEL 'channel_name'G
If both threads are Yes, skip the START command. If one thread is No, STOP the channel cleanly and then START it again.
Automated failover loop: add a conditional check that only calls START when Slave_SQL_Running='No'.
Manual maintenance: run STOP SLAVE FOR CHANNEL 'channel_name' before re-starting to apply new parameters safely.
Make START SLAVE idempotent by wrapping it in scripts that test IO and SQL thread states.
Leverage replication_metadata_repository=TABLE so MySQL persists channel status across restarts, reducing ambiguity.
Error 3084 ER_SLAVE_CHANNEL_WAS_NOT_RUNNING occurs when STOP SLAVE is executed on an already-stopped channel; the remedy is symmetrical: check status before STOP.
Error 1872 ER_SLAVE_MASTER_INFO applies when master info repositories conflict; resync metadata or recreate the channel.
Failover tools sometimes loop through channels and issue START SLAVE blindly, resulting in Error 3083 on those already running.
DBAs may run START SLAVE twice during troubleshooting, unaware that the first command succeeded.
Configuration management systems may think replication is stopped due to stale inventory data, sending redundant START commands.
Raised when STOP SLAVE targets an already stopped channel. Solution: check status before stopping.
Indicates corrupted or mismatched master info. Recreate channel metadata.
Occurs when replica cannot read master's binlog. Requires binlog position correction or re-sync.
No. Replication continues to run. The error only signals a redundant START command.
Wrap START SLAVE in a status check or ignore error 3083 in orchestration scripts to keep logs clean.
The error is transient. It disappears once no redundant START command is issued after restart.
Galaxy's SQL editor surfaces replication status queries and AI-generated fixes, making it easy to build idempotent automation without copy-paste errors.
.avif)
.avif){kind=logo}
