MetricDataQuery class
This structure is used in both GetMetricData
and
PutMetricAlarm
. The supported use of this structure is
different for those two operations.
When used in GetMetricData
, it indicates the metric data to
return, and whether this call is just retrieving a batch set of data for one
metric, or is performing a math expression on metric data. A single
GetMetricData
call can include up to 500
MetricDataQuery
structures.
When used in PutMetricAlarm
, it enables you to create an alarm
based on a metric math expression. Each MetricDataQuery
in the
array specifies either a metric to retrieve, or a math expression to be
performed on retrieved metrics. A single PutMetricAlarm
call
can include up to 20 MetricDataQuery
structures in the array.
The 20 structures can include as many as 10 structures that contain a
MetricStat
parameter to retrieve a metric, and as many as 10
structures that contain the Expression
parameter to perform a
math expression. Of those Expression
structures, one must have
True
as the value for ReturnData
. The result of
this expression is the value the alarm watches.
Any expression used in a PutMetricAlarm
operation must return a
single time series. For more information, see Metric
Math Syntax and Functions in the Amazon CloudWatch User Guide.
Some of the parameters of this structure also have different uses whether
you are using this structure in a GetMetricData
operation or a
PutMetricAlarm
operation. These differences are explained in
the following parameter list.
Constructors

MetricDataQuery({@_s.required String id,
String expression, String label, MetricStat metricStat, int period, bool returnData} ) 
MetricDataQuery.fromXml(XmlElement elem
) 
factory
Properties
 expression → String

The math expression to be performed on the returned data, if this object is
performing a math expression. This expression can use the
Id
of the other metrics to refer to those metrics, and can also use theId
of other expressions to use the result of those expressions. For more information about metric math expressions, see Metric Math Syntax and Functions in the Amazon CloudWatch User Guide. [...]final  hashCode → int

The hash code for this object. [...]
readonly, inherited
 id → String

A short name used to tie this object to the results in the response. This
name must be unique within a single call to
GetMetricData
. If you are performing math expressions on this set of data, this name represents that data and can serve as a variable in the mathematical expression. The valid characters are letters, numbers, and underscore. The first character must be a lowercase letter.final  label → String

A humanreadable label for this metric or expression. This is especially
useful if this is an expression, so that you know what the value represents.
If the metric or expression is shown in a CloudWatch dashboard widget, the
label is shown. If Label is omitted, CloudWatch generates a default.
final
 metricStat → MetricStat

The metric to be returned, along with statistics, period, and units. Use
this parameter only if this object is retrieving a metric and not performing
a math expression on returned data. [...]
final
 period → int

The granularity, in seconds, of the returned data points. For metrics with
regular resolution, a period can be as short as one minute (60 seconds) and
must be a multiple of 60. For highresolution metrics that are collected at
intervals of less than one minute, the period can be 1, 5, 10, 30, 60, or
any multiple of 60. Highresolution metrics are those metrics stored by a
PutMetricData
operation that includes aStorageResolution of 1 second
.final  returnData → bool

When used in
GetMetricData
, this option indicates whether to return the timestamps and raw data values of this metric. If you are performing this call just to do math expressions and do not also need the raw data returned, you can specifyFalse
. If you omit this, the default ofTrue
is used. [...]final  runtimeType → Type

A representation of the runtime type of the object.
readonly, inherited
Methods

noSuchMethod(
Invocation invocation ) → dynamic 
Invoked when a nonexistent method or property is accessed. [...]
inherited

toString(
) → String 
Returns a string representation of this object.
inherited
Operators

operator ==(
dynamic other ) → bool 
The equality operator. [...]
inherited