<p>The heartbeat period configured for a replica exceeds the slave_net_timeout value, causing MySQL to raise error 1704.</p>
<p>MySQL Error 1704 ER_SLAVE_HEARTBEAT_VALUE_OUT_OF_RANGE_MAX occurs when the replica heartbeat period is set higher than slave_net_timeout. Lower the heartbeat period or raise slave_net_timeout to resolve the issue.</p>
The requested value for the heartbeat period exceeds the
The error appears when a CHANGE MASTER TO or START SLAVE statement requests a heartbeat period that is longer than the current slave_net_timeout setting. MySQL blocks the change to prevent silent replication failures.
The message protects replica stability. If the replica waits longer than slave_net_timeout seconds without a heartbeat, it considers the source unreachable and reconnects. A larger heartbeat period would delay this detection, so MySQL rejects it.
The error surfaces during replication configuration on MySQL 5.5 and newer. It is most common after modifying replica settings or upgrading servers where default timeout values differ.
Automated orchestration tools and GUI wizards can also trigger the fault if they generate an out-of-range heartbeat parameter.
Leaving the configuration unchanged breaks replication startup. The replica will not fetch or apply binary logs, causing data lag. Production systems relying on eventual consistency will diverge from the primary database.
Setting MASTER_HEARTBEAT_PERIOD to a value equal to or higher than slave_net_timeout during CHANGE MASTER TO.
Low slave_net_timeout values inherited from defaults or previous tuning while using a higher heartbeat suggestion.
Mismatched configuration between primary and replica after version upgrades.
Choose one of two approaches: reduce the heartbeat period or increase slave_net_timeout. The sum must satisfy heartbeat period < slave_net_timeout.
After adjusting, restart or reissue START SLAVE to apply changes.
Scenario: heartbeat requested at 60 seconds, slave_net_timeout at 30. Solution: set MASTER_HEARTBEAT_PERIOD = 15 or raise slave_net_timeout = 90.
Scenario: orchestrator auto-generates 0.9*slave_net_timeout but timeout is 1, triggering failure. Solution: set timeout 10 or heartbeat 0.5.
Maintain slave_net_timeout at least 2 times larger than expected network jitter. Derive heartbeat as 0.5*slave_net_timeout for headroom.
Template configuration files for all replicas to ensure uniform settings during provisioning. Automate validation checks in CI pipelines or with Galaxy pre-flight scripts.
Error 1201: HY000 Master timeout - occurs when no heartbeat or events received within slave_net_timeout. Align heartbeat correctly.
Error 1872: SLAVE_HEARTBEAT_VALUE_OUT_OF_RANGE_MIN - fired when heartbeat period is below minimum 1 millisecond.
A direct mismatch during CHANGE MASTER TO sets the heartbeat out of range.
Upgrading can lower default slave_net_timeout from 3600 to 60 seconds, invalidating existing heartbeat settings.
Different replicas receive inconsistent timeout parameters due to manual edits or missing Ansible values.
Heartbeat period below 1 microsecond. Raise period or remove setting.
Replica did not receive data or heartbeat within slave_net_timeout. Investigate network or source stall.
Network read failure between source and replica. Check SSL, firewalls, or bandwidth saturation.
Keep heartbeat at 0.1 to 0.5 of slave_net_timeout so the replica detects failures promptly without excessive traffic.
Yes. Setting MASTER_HEARTBEAT_PERIOD=0 makes MySQL auto choose 0.5*slave_net_timeout. Ensure timeout is suitable.
No. It is a dynamic global variable. However, edit my.cnf to make the change persistent across restarts.
Galaxy highlights variable mismatches in replica setup scripts and offers AI-driven linting that warns when heartbeat exceeds slave_net_timeout before execution.
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