MySQL GTID replication, slave read executed binlogs, failed to get the latest binlog MySQL VERSION: Server version:        5.7.19-17-log Source distribution
Replication mode: mysql multi source replication: MySQL-C works as slave for MySQL-A(source1) and MySQL-B(source2);  real  topology as follows:

current state:


  channel 1( A-C),  both IO and SQL_THREAD works well, relay-log from A (parsed by mysqlbinlog), all gtids in relay-log are executed in Executed_Gtid_Set. 
  channel 2( B-C), works fine.
One workaround for this condition is finding corresponding binlog-file and binlog-pos according to the Executed_Gtid_Set from show slave status.  Change GTID-Based replication to File-Postion replication.