Could it be that your slaves are periodically disconnecting from the master and then reconnecting again, and you just happened to catch a state when only one slave is connected when you queried for Rpl_semi_sync_master_clients status? To confirm or deny this you should look at the master's error log to see if there are periodically repeating messages "Starting semi-sync replication". Regarding your config: your email suggests that you have rpl_semi_sync_master_enabled set to ON on slaves. Is that really true? Such setting on the slaves will probably work only if log_slave_updates is set to OFF. Is it set to OFF on your slaves? If not then you should set rpl_semi_sync_master_enabled to OFF on the slaves to not make them wait for their slaves (which don't exist) to ack the commits. On Fri, Mar 24, 2017 at 3:02 AM, Ljr Yang <dbmsprog@gmail.com> wrote:
HI, we have many groups master slave , used semi-sync are normal. but there a group master and slave , semi-sync status show have a little question.
master: 10.1.0.61 (MariaDB 10.1.22) slave1 : 10.1.0.62 (MariaDB 10.1.22) slave2: 10.1.0.63 (MariaDB 10.1.22)
three machine's semi-sync parameter: rpl_semi_sync_master_enabled ON rpl_semi_sync_master_timeout 10000 rpl_semi_sync_master_wait_point AFTER_COMMIT rpl_semi_sync_slave_enabled ON
on master: SHOW GLOBAL STATUS LIKE '%semi%' ; Rpl_semi_sync_master_clients 1 # should show : 2 ......
on slave1: stop slave io_thread; then on master: SHOW GLOBAL STATUS LIKE '%semi%' ; Rpl_semi_sync_master_clients ０
on slave1: start slave io_thread; on master: SHOW GLOBAL STATUS LIKE '%semi%' ; Rpl_semi_sync_master_clients 1
on slave2: stop slave io_thread; then on master: SHOW GLOBAL STATUS LIKE '%semi%' ; Rpl_semi_sync_master_clients ０
on slave2: start slave io_thread; on master: SHOW GLOBAL STATUS LIKE '%semi%' ; Rpl_semi_sync_master_clients 1
on slave1 and slave2 , I had uninstall and reinstall semi-sync plugin, still show Rpl_semi_sync_master_clients is 1
I don't know where config have question? please you help, thanks
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