bugzillaId-589: detect if MAXSCALE_SCHEMA.HEARTBEAT table is not replicated

This item is imported from bugzilla http://bugs.mariadb.com/show_bug.cgi?id=589

Vilho Raatikka 2014-10-22 12:40:44 UTC
If replication lag is also monitored, monitor user must have enough permissions to create schema, insert and read rows from its tables. That's because MaxScale creates MAXSCALE_SCHEMA and HEARTBEAT table in it.

[MySQL Monitor]

type=monitor

module=mysqlmon

servers=server1,server2,server3

user=maxuser

passwd=maxpwd

# 

# options for mysql_monitor only

#

detect_replication_lag=1

MySQL replication setup may limit what is replicated. If MAXSCALE_SCHEMA.HEARTBEAT isn't replicated replication lag can't be resolved for any of the slaves. As a consequence, all queries are routed to master.

What is asked is detection of this situation and such a log write to error and trace log that user recognizes the case.