MySQL-wsrep does not replicate Innodb memcached plugin writes

[Jay Janssen]

3 node cluster following example here: http://dev.mysql.com/doc/refman/5.6/en/innodb-memcached-setup.html

[root@node1 ~]# mysql < /usr/share/mysql/innodb_memcached_config.sql

Set these settings: (based on http://dev.mysql.com/doc/refman/5.6/en/innodb-memcached-replication.html)
log-bin
innodb_api_enable_binlog = ON

[root@node1 ~]# service mysql restart

But when I write to a row, it does not replicate:

# telnet 127.0.0.1 11211
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is '^]'.
get all
VALUE all 10 9
123456789
END
get AA
VALUE AA 8 12
HELLO, HELLO
END
set BB 0 0 1
0
STORED
^]
telnet> quit
Connection closed.

[root@node1 mysql]# telnet 127.0.0.1 11211
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is '^]'.
incr BB 1
1
incr BB 1
2
^]
telnet> ^]
?Invalid command
telnet> quit
Connection closed.

node1 mysql> select * from demo_test;
+-----+--------------+------+------+------+
| c1 | c2 | c3 | c4 | c5 |
+-----+--------------+------+------+------+
| AA | HELLO, HELLO | 8 | 0 | 0 |
| all | 123456789 | 10 | 2 | 0 |
| BB | 2 | 0 | 3 | 0 |
+-----+--------------+------+------+------+
3 rows in set (0.00 sec)

But the other nodes do not get the new rows or updates:

node3 mysql> select * from demo_test;
+----+--------------+------+------+------+
| c1 | c2 | c3 | c4 | c5 |
+----+--------------+------+------+------+
| AA | HELLO, HELLO | 8 | 0 | 0 |
+----+--------------+------+------+------+
1 row in set (0.00 sec)

There are no errors in replication, the cluster otherwise behaves normally.

[Chris Tomlinson (chris-tomlinson)]

This is only a problem if you enable innodb_api_enable_binlog.

We are running an innodb memcache plugin on our cluster with binlog enabled and ws_rep replicates just fine within the Percona cluster.

We are not interested in replicating the contents of our memcache tables to the async backup servers that slave off our main cluster so we just leave innodb_api_enable_binlog disabled.

[Dom (launchpal)]

What's the status/diagnosis of this issue? Does PXC provide replicated memcache interface? It's a potentially huge feature for clustering websites (sessions).

[Dom (launchpal)]

@Chris, I've tried using a standard setup as specified in the mysql documentation, except disabling innodb_api_enable_binlog, and wsrep doesn't replicate anything stored through memcached interface.
The documentation for the memcached interface does indicate that it uses RBR, so I would expect it to work, but it doesn't seem to :(

[Dom (launchpal)]

Looks like this is not implemented at the wsrep level but it has been requested:
https://github.com/codership/mysql-wsrep/issues/230

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PXC-1525