1667
MariaDBERRORCommonReplicationHIGH confidence
Multi-threaded replication recovery failed
Production Risk
High — replica data integrity is uncertain; re-provisioning is the safest path.
What this means
The automatic recovery mechanism for multi-threaded slave (MTS) replication failed to reconcile worker threads after an unclean shutdown.
Why it happens
- 1The relay log was damaged or missing, preventing gap detection.
- 2relay_log_recovery=ON could not automatically recover the relay log state.
- 3The MTS checkpoint was too far behind to allow automatic recovery.
How to reproduce
trigger — this will error
trigger — this will error
-- Restart after unclean shutdown with slave_parallel_workers > 0
expected output
ERROR 1667 (HY000): Recovery from master pos and file for channel failed.
Fix
Re-provision the replica from a fresh backup
Re-provision the replica from a fresh backup
STOP SLAVE; RESET SLAVE ALL; -- Restore from backup, then: CHANGE MASTER TO ... START SLAVE;
Why this works
A fresh start from a known-good backup eliminates unrecoverable relay log gaps.
What not to do
✕
Version notes
Sources
Official documentation ↗
MySQL 8.0 — 1667 ER_MTS_RECOVERY_FAILURE
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