1754
MariaDBERRORNotableReplicationHIGH confidence
MTS: number of updated databases exceeds limit
Production Risk
High — replication halted.
What this means
Under MTS parallel replication, a single transaction updated more databases than the internal tracking limit allows, preventing correct worker assignment.
Why it happens
- 1A single binlog event touches more distinct databases than the MTS can track (default limit: 254).
How to reproduce
trigger — this will error
trigger — this will error
-- Caused by extremely large cross-database transactions during MTS replication
expected output
ERROR 1754 (HY000): Multi-threaded slave: Too many workers updated the same database.
Fix
Reduce cross-database transaction scope or disable MTS
Reduce cross-database transaction scope or disable MTS
SET GLOBAL slave_parallel_workers = 0;
Why this works
Single-threaded replication has no database-count limit.
What not to do
✕
Sources
Official documentation ↗
MySQL 8.0 — 1754 ER_MTS_UPDATED_DBS_GREATER_MAX
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