MetricDataQuery
The metric data to return. Also defines whether this call is returning data for one metric only, or whether it is performing a math expression on the values of returned metric statistics to create a new time series. A time series is a series of data points, each of which is associated with a timestamp.
You can use MetricDataQuery
structures with a
PutScalingPolicy
operation when you specify a PredictiveScalingConfiguration
in the request. Predictive scaling uses the time series data received from CloudWatch to understand how to schedule capacity based on
your historical workload patterns.
You can call for a single metric or perform math expressions on multiple metrics. Any expressions used in a metric specification must eventually return a single time series.
For more information and examples, see Advanced predictive scaling policy configurations using custom metrics in the Amazon EC2 Auto Scaling User Guide.
Contents
 Id

A short name that identifies the object's results in the response. This name must be unique among all
MetricDataQuery
objects specified for a single scaling policy. 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 underscores. The first character must be a lowercase letter.Type: String
Length Constraints: Minimum length of 1. Maximum length of 255.
Pattern:
[\u0020\uD7FF\uE000\uFFFD\uD800\uDC00\uDBFF\uDFFF\r\n\t]*
Required: Yes
 Expression

The math expression to perform 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.Conditional: Within each
MetricDataQuery
object, you must specify eitherExpression
orMetricStat
, but not both.Type: String
Length Constraints: Minimum length of 1. Maximum length of 1023.
Pattern:
[\u0020\uD7FF\uE000\uFFFD\uD800\uDC00\uDBFF\uDFFF\r\n\t]*
Required: No
 Label

A humanreadable label for this metric or expression. This is especially useful if this is a math expression, so that you know what the value represents.
Type: String
Length Constraints: Maximum length of 2047.
Pattern:
[\u0020\uD7FF\uE000\uFFFD\uD800\uDC00\uDBFF\uDFFF\r\n\t]*
Required: No
 MetricStat

Information about the metric data to return.
Conditional: Within each
MetricDataQuery
object, you must specify eitherExpression
orMetricStat
, but not both.Type: MetricStat object
Required: No
 ReturnData

Indicates whether to return the timestamps and raw data values of this metric.
If you use any math expressions, specify
true
for this value for only the final math expression that the metric specification is based on. You must specifyfalse
forReturnData
for all the other metrics and expressions used in the metric specification.If you are only retrieving metrics and not performing any math expressions, do not specify anything for
ReturnData
. This sets it to its default (true
).Type: Boolean
Required: No
See Also
For more information about using this API in one of the languagespecific Amazon SDKs, see the following: