3302
MariaDBERRORCommonReplicationHIGH confidence
Replica has the same server-id as the source — circular replication loop detected
Production Risk
Critical — replication stops entirely; the replica falls behind the source.
How to reproduce
trigger — this will error
trigger — this will error
-- SET @@GLOBAL.server_id = <same value as source>; then START REPLICA;
expected output
ERROR 3302 (HY000): The slave I/O thread stops because master and slave have equal MySQL server ids; these ids must be different for replication to work.
Fix
Set a unique server_id
Set a unique server_id
SET GLOBAL server_id = 3; STOP REPLICA; START REPLICA;
Why this works
Each node must have a globally unique server_id within the topology.
What not to do
✕
Sources
Official documentation ↗
MySQL 8.0 — 3302 ER_SLAVE_SAME_ID_SERVER
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