This warning appears when CHANGE MASTER TO includes MASTER_LOG_FILE but omits MASTER_LOG_POS, risking an unsafe replication start position.
MySQL error 3023 (ER_WARN_ONLY_MASTER_LOG_FILE_NO_POS) arises when you run CHANGE MASTER TO with MASTER_LOG_FILE but forget MASTER_LOG_POS. Supply the correct MASTER_LOG_POS or omit both parameters to resolve the warning.
ER_WARN_ONLY_MASTER_LOG_FILE_NO_POS
Error 3023 is a replication configuration warning introduced in MySQL 5.7.4. It appears when you issue CHANGE MASTER TO with the MASTER_LOG_FILE option but omit MASTER_LOG_POS. MySQL warns that starting replication at file level only may replay or skip transactions, causing data drift.
The server still accepts the statement, yet the replication start point may be unsafe because the stored position could belong to the previous binary log. Fixing the mismatch is essential before promoting the replica or resuming replication.
The warning is triggered whenever CHANGE MASTER TO specifies a new MASTER_LOG_FILE while leaving the MASTER_LOG_POS unchanged or absent. MySQL detects that the saved position was recorded from a different file and flags potential inconsistency.
Automation scripts, manual failover, or restoring from backups often produce this state by populating only the file name. Mixing GTID and file/position replication also creates scenarios where positions are ignored.
First, query the master's current binary log and position with SHOW MASTER STATUS. Next, rerun CHANGE MASTER TO specifying both MASTER_LOG_FILE and the exact MASTER_LOG_POS. Finally, START SLAVE (or START REPLICA in 8.0) and verify that Seconds_Behind_Master is acceptable.
During point-in-time recovery, fetch the log file and position embedded in the dump's CHANGE MASTER TO line, not the latest file. When performing failover with an orchestration tool, double-check that it sets both parameters. If you switched to GTID, drop file-based coordinates entirely by removing both clauses.
Always script CHANGE MASTER TO with both MASTER_LOG_FILE and MASTER_LOG_POS captured together. Use SHOW BINLOG EVENTS to confirm that the chosen position aligns with transaction boundaries. Enable GTID replication to eliminate manual file/position management and rely on global transaction IDs.
Errors 1201 and 1203 indicate IO and SQL thread failures that often follow incorrect start positions. ER_MASTER_FATAL_ERROR_READING_BINLOG shows when the replica cannot read the supplied file. Resolving 3023 early prevents these critical follow-ups.
The administrator copies only the file name from the master and omits the matching byte position.
The replica had a valid position, then the file was changed without updating the coordinate.
Custom automation builds CHANGE MASTER TO strings that lack the position token.
A configuration rollback disables GTID but leaves position values unset.
Replication fails because the replica cannot find or read the specified file or position.
The SQL thread stops after hitting an invalid event due to misaligned file/pos.
Relay log corruption often follows an unsafe restart point.
Heartbeat issues can accompany replication misconfiguration.
No, it is a warning, but ignoring it can lead to data inconsistency.
You can run SET sql_notes=0 before CHANGE MASTER TO, but fixing the coordinates is safer.
GTID mode normally skips file/pos, so switching to GTID removes the condition entirely.
Galaxy stores vetted replication commands in shared Collections, reducing manual edits that cause 3023.
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