EC
3085
MySQLERRORNotableReplicationHIGH confidence

Cannot change sql_log_bin inside a stored function or trigger

Production Risk

High — trigger/function fails and the DML is rolled back.

What this means

The sql_log_bin session variable cannot be changed from within a stored function or trigger.

Why it happens
  1. 1SET SESSION sql_log_bin used inside a stored function or trigger body.
How to reproduce
trigger — this will error
trigger — this will error
CREATE TRIGGER trg BEFORE INSERT ON t FOR EACH ROW SET SESSION sql_log_bin = 0;

expected output

ERROR 3085 (HY000): Cannot change the sql_log_bin inside a stored function or trigger.

Fix

Set sql_log_bin at the session level before invoking the routine

Set sql_log_bin at the session level before invoking the routine
SET SESSION sql_log_bin = 0;
INSERT INTO t VALUES (1);
SET SESSION sql_log_bin = 1;

Why this works

Session-level control outside the trigger avoids the restriction.

What not to do

✕

Sources
Official documentation ↗

MySQL 8.0 — 3085 ER_STORED_FUNCTION_PREVENTS_SWITCH_SQL_LOG_BIN2

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