| Bug #78746 | mysqlrpladmin switchover does not change the read_only setting | ||
|---|---|---|---|
| Submitted: | 8 Oct 2015 3:27 | Modified: | 22 Nov 2016 10:27 |
| Reporter: | monty solomon | Email Updates: | |
| Status: | Duplicate | Impact on me: | |
| Category: | MySQL Utilities | Severity: | S1 (Critical) |
| Version: | 1.5.6 | OS: | Any |
| Assigned to: | CPU Architecture: | Any | |
[8 Oct 2015 4:24]
monty solomon
The following statement in set_read_only() is missing parentheses
return self.exec_query("SET @@GLOBAL.READ_ONLY = %s" %
"ON" if on else "OFF")
It should read
return self.exec_query("SET @@GLOBAL.READ_ONLY = %s" %
("ON" if on else "OFF"))
[8 Oct 2015 4:37]
monty solomon
The code sets the master to be read-only then it stops all the slaves and then it erroneously sets the master to be read-write again. The master should stay blocked and read-only. Only if the master is demoted and connected as a slave to the promoted master should it be set to read-write again.
lock_ftwrl = Lock(self.master, [], lock_options)
self.master.set_read_only(True)
...
# Stop all slaves
self._report("# Stopping slaves.")
self.run_cmd_on_slaves("stop", not self.verbose)
# Unblock master
self.master.set_read_only(False)
lock_ftwrl.unlock()
[8 Oct 2015 4:41]
monty solomon
The code to demote the master does not change the read-only setting on the demoted master. It may assume that demoted master was left in a read-only state.
[8 Oct 2015 5:08]
monty solomon
The code does not set the promoted master to be read/write. The failover() method should be checked to make sure it does not have similar issues.
[3 Nov 2016 10:53]
Flex Gao
Still has this problem on 1.6.4
[22 Nov 2016 10:27]
Chiranjeevi Battula
Hello monty solomon, Thank you for the bug report. This is most likely duplicate of Bug #76522, please see Bug #76522. Thanks, Chiranjeevi.
Description: After executing the mysqlrpladmin switchover command the new master is still running in read-only mode and the old master is still running in read-write mode. mysqlrpladmin does not change the master to read_only before swapping roles. How to repeat: Create a master/slave cluster and check the read_only settings on the master and the slave to become the new master % mysql -h lively-mode -sNe'select @@read_only' 0 % mysql -h bitter-unit -sNe'select @@read_only' 1 Execute mysqlrpladmin to switch the master % mysqlrpladmin switchover --verbose --discover-slaves-login=.myrpladmin.cnf[lively-mode] --master=.myrpladmin.cnf[lively-mode] --new-master=.myrpladmin.cnf[bitter-unit] --rpl-user=SUSR_Repl:redacted --log=mysqlrpladmin.log --demote-master Check the read_only settings on the new master and former master and observe that they were not changed % mysql -h bitter-unit -sNe'select @@read_only' 1 % mysql -h lively-mode -sNe'select @@read_only' 0 Suggested fix: Change the following line in connect() in server.py to set the value to True/False instead of to ON/OFF self.read_only = self.show_server_variable("READ_ONLY")[0][1] or change the following line in set_read_only() in server.py to check for the value ON/OFF instead of True/False if not self.read_only: