EC
1756
MariaDBERRORCommonReplicationHIGH confidence

MTS: inconsistent data detected

Production Risk

Critical — replica data may be corrupt.

What this means

Multi-Threaded Slave detected that the replica data has become inconsistent with the master due to a parallel execution error.

Why it happens
  1. 1A worker thread applied events out of logical order.
  2. 2A prior MTS error was not resolved before resuming replication.
How to reproduce
trigger — this will error
trigger — this will error
-- Internal MTS error; surfaces after worker failures

expected output

ERROR 1756 (HY000): Multi-threaded slave: Inconsistent data detected.

Fix

Rebuild the replica from a fresh backup

Rebuild the replica from a fresh backup
-- Restore from master backup, then:
CHANGE MASTER TO MASTER_LOG_FILE='...', MASTER_LOG_POS=...;
START SLAVE;

Why this works

Ensures the replica starts from a known-good consistent state.

What not to do

✕

Sources
Official documentation ↗

MySQL 8.0 — 1756 ER_MTS_INCONSISTENT_DATA

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