<p>MySQL throws error 1779 when GTID_MODE is set to ON while ENFORCE_GTID_CONSISTENCY remains OFF.</p>
<p>MySQL Error 1779: ER_GTID_MODE_ON_REQUIRES_ENFORCE_GTID_CONSISTENCY_ON means you enabled GTID transactions without also enabling enforce_gtid_consistency. Turn on ENFORCE_GTID_CONSISTENCY or switch GTID_MODE back to OFF to fix the issue.</p>
GTID_MODE = ON requires ENFORCE_GTID_CONSISTENCY = ON.
Error 1779 appears with the message "GTID_MODE = ON requires ENFORCE_GTID_CONSISTENCY = ON" whenever you enable global transaction identifiers (GTIDs) but leave enforce_gtid_consistency disabled. The server refuses the configuration because inconsistent statements break GTID guarantees.
The error was introduced in MySQL 5.7.6 and affects all later versions, including 8.x. It can surface during server startup, runtime configuration changes, or replication setup scripts.
GTID replication relies on every transaction being safely logged and re-playable on replicas. Non-deterministic or unsafe statements can corrupt replica state. ENFORCE_GTID_CONSISTENCY blocks those statements, so MySQL mandates it before you can switch GTID_MODE to ON.
Without the consistency flag, statements like CREATE TABLE ... SELECT or UPDATE with LIMIT are allowed, leading to divergent data on replicas. Error 1779 prevents that risk.
Administrators often hit the error while migrating an existing server to GTID replication. It also appears in containerized images where only GTID_MODE is toggled via environment variables. Runtime changes with SET @@GLOBAL.gtid_mode = ON fail if ENFORCE_GTID_CONSISTENCY is OFF.
The error may be buried in startup logs, causing the server to remain in OFF_PERMISSIVE mode rather than the desired ON state.
Failure to enable GTID replication means you lose automatic failover and simpler replica promotion. Mixed GTID and non-GTID servers complicate recovery procedures, lengthen downtime, and increase data-loss risk.
Only gtid_mode=ON was added to the configuration file, leaving enforce_gtid_consistency unspecified or OFF.
An administrator issued SET GLOBAL gtid_mode = ON before enabling enforce_gtid_consistency during an online migration.
DevOps templates or Docker images toggle GTID_MODE with environment variables but omit the corresponding consistency flag.
The consistency flag was enabled, then disabled later in the same script before GTID_MODE was activated.
Occurs when GTID_MODE is ON but binary logging is disabled.
Triggers when CREATE TABLE ... SELECT is executed without GTID consistency enforced.
Happens if you try to change GTID_MODE while there are ongoing transactions.
Yes. The change only blocks unsafe statements; regular DML continues unaffected.
No. MySQL will reject the change while GTID_MODE is ON to protect replication integrity.
No. The variable pair was introduced in 5.7.6, so 5.6 servers never raise this error.
Galaxy surfaces server variables in its sidebar and flags conflicting settings, guiding you to enable both options before running migration scripts.
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