MySQL 8.0 Reference Manual Including MySQL NDB Cluster 8.0
SELECT MASTER_POS_WAIT('source_log_file
',source_log_pos
[,timeout
][,channel
])
This is actually a function, not a statement. It is used to ensure that the replica has read and executed events up to a given position in the source's binary log. See Section 12.24, “Miscellaneous Functions”, for a full description.