1273
MySQLerrorreplicationhigh confidence
Slave is already running
Production Risk
Low — harmless error; replication continues normally.
What this means
START SLAVE (or START REPLICA) was issued but the replica SQL or IO thread is already running.
Why it happens
- 1Issuing START SLAVE twice
- 2Automation script not checking thread state before starting
How to reproduce
trigger — this will error
trigger — this will error
START SLAVE;
expected output
ERROR 1273 (HY000): Slave is already running
Fix
Check replica status first
Check replica status first
SHOW SLAVE STATUS\G
Why this works
Inspect Slave_IO_Running and Slave_SQL_Running before issuing START SLAVE.
What not to do
✕
Version notes
Sources
Official documentation ↗
MySQL 8.0 — 1273 ER_SLAVE_WAS_RUNNING
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