pt-sync-table does not support multiple replication channels

[Alexander]

pt-sync-table doesn't know how to handle case when slave has more than 1 master connected.

user@slave1 PTDEBUG=1 pt-table-sync --print --databases my_site --replicate percona.checksums --sync-to-master 'h=127.0.0.1,P=3306,u=check,p=check_pass' -v

percona-toolkit 2.2.17-1

Master MySQL: Percona MySQL 5.7.11-4
Slaves MySQL: Oracle MySQL 5.7.9

Console output:
[skipped]

# TableSyncer:6163 25683 Executing statement on source to lock rows
# TableSyncer:6166 25683 DBI::db=HASH(0x1c9ad50) START TRANSACTION /*!40108 WITH CONSISTENT SNAPSHOT */
# Retry:8348 25683 Try 1 of 3
# MasterSlave:6906 25683 DBI::db=HASH(0x1c9d7a8) SHOW MASTER STATUS
# MasterSlave:6910 25683 Binlog_Do_DB= Position=357679626 Binlog_Ignore_DB= Executed_Gtid_Set=63e110f8-1ddf-11e6-8561-002590c2fa54:1-5574135 File=mysql-bin.000040
# MasterSlave:6935 25683 DBI::db=HASH(0x1c9e060) SELECT MASTER_POS_WAIT('mysql-bin.000040', 357679626, 60)
# Retry:8354 25683 Try code failed: DBD::mysql::db selectrow_array failed: fetch() without execute() [for Statement "SELECT MASTER_POS_WAIT('mysql-bin.000040', 357679626, 60)"] at /usr/bin/pt-table-sync line 6937.
#
MASTER_POS_WAIT() returned NULL. Verify that the slave is running. Sleeping 10 seconds then retrying 2 more times.
# Retry:8360 25683 Calling wait code
^C

Strace logging:
[skipped]

write(3, ":\0\0\0\3SELECT MASTER_POS_WAIT('mysql-bin.000040', 355702326, 60)", 62) = 62
read(3, "\1\0\0\1\1H\0\0\2\3def\0\0\0002MASTER_POS_WAIT('mysql-bin.000040', 355702326, 60)\0\f?\0\25\0\0\0\10\200\0\0\0\0\5\0\0\3\376\0\0\0\0Z\0\0\4\377\7\f#HY000Multiple channels exist on the slave. Please provide channel name as an argument.", 16384) = 184
write(2, "MASTER_POS_WAIT() returned NULL. Verify that the slave is running. Sleeping 10 seconds then retrying 2 more times.\n", 117) = 117

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PT-1350