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Config value for copydb ReplicatedMasterPositionQuery with vanilla MysQL replication #348
Description
Hello, I am trying to use the ReplicatedMasterPositionQuery config when setting the source as replica.
The example in the config is showing a query using pt-heartbeat
Line 70 in 82e0615
When using vanilla MySQL replication ( using 8.0.34 ), what query should I be using?
It seems
SHOW REPLICA STATUS; contains the adequate information ( Relay_Source_Log_Pos, Relay_Source_Log_File ), however I am not able to extract them through a SELECT query. Am I missing a config to use?
Looking into it, there are some tables related to replication in the performance schema https://dev.mysql.com/doc/refman/8.0/en/performance-schema-replication-tables.html, however it states the following:
The information in the Performance Schema replication tables differs somewhat from the information available from SHOW REPLICA STATUS because the tables are oriented toward use of global transaction identifiers (GTIDs), not file names and positions, and they represent server UUID values, not server ID values. Due to these differences, several SHOW REPLICA STATUS columns are not preserved in the Performance Schema replication tables, or are represented a different way:
The following fields refer to file names and positions and are not preserved:
Master_Log_File
Read_Master_Log_Pos
Relay_Log_File
Relay_Log_Pos
Relay_Master_Log_File
Exec_Master_Log_Pos
Until_Condition
Until_Log_File
Until_Log_Pos
So it does not seems that it could be used.
Thanks!
Activity
driv3r commentedon Oct 14, 2026
For vanilla replication, run in GTID mode (
BinlogCoordinateMode: "gtid") and setReplicatedMasterGTIDQuery(copydb/config.go) to a query returning the master's executed GTID set as seen by the replica. If the replica takes no local writes and replicates from a single source,SELECT @@GLOBAL.gtid_executedworks. In file/position mode the custom query must return a single(file, position)row, soSHOW REPLICA STATUScan't be used directly. Closing as answered.