String values may appear in the Expression
or
the Thresholds
text boxes. In both cases,
they must be enclosed within quotation marks. For example, the
expression for the “Slave I/O Thread Not Running”
rule is:
(%Slave_running% == "ON") && (%Slave_IO_Running% != THRESHOLD)
In similar fashion the Critical Alerts
threshold text box is set to a value of
"Yes"
.
When the expression is evaluated, either
"OFF"
or "ON"
will be
substituted for %Slave_running%
, and
"Yes"
or "No"
for
%Slave_IO_Running%
, depending on the state of
your system. If the slave is running but the I/O thread is not,
the expression then becomes:
("ON" == "ON") && ("No" != "Yes")
Without quotation marks this expression would not evaluate to
TRUE
as it should.
So that it is interpreted properly, the ==
operator is converted to =
before being
passed to the MySQL expression parser.