Metrics Insights query components and syntax - Amazon CloudWatch

Metrics Insights query components and syntax

CloudWatch Metrics Insights syntax is as follows.

SELECT FUNCTION(metricName) FROM namespace | SCHEMA(...) [ WHERE labelKey OPERATOR labelValue [AND ... ] ] [ GROUP BY labelKey [ , ... ] ] [ ORDER BY FUNCTION() [ DESC | ASC ] ] [ LIMIT number ]

The possible clauses in a Metrics Insights query are as follows. None of the keywords are case sensitive, but the identifiers such as the names of metrics, namespaces, and dimensions are case sensitive.

SELECT

Required. Specifies the function to use to aggregate observations in each time bucket (detemined by the provided period). Also specifies the name of the metric to query.

The valid values for FUNCTION are AVG, COUNT, MAX, MIN, and SUM.

  • AVG calculates the average of the observations matched by the query.

  • COUNT returnst the count of the observations matched by the query.

  • MAX returns the maximum value of the observations matched by the query.

  • MIN returns the minimum value of the observations matched by the query.

  • SUM calculates the sum of the observations matched by the query.

FROM

Required. Specifies the source of the metric. You can specify either the metric namespace that contains the metric that is to be queried, or a SCHEMA table function. Examples of metric namespaces include "AWS/EC2", "AWS/Lambda", and metric namespaces that you have created for your custom metrics.

Metric namespaces that include / or any other character that is not a letter, number, or underscore must be surrounded by double quotation marks. For more information, see What needs quotation marks or escape characters?.

SCHEMA

An optional table function that can be used within a FROM clause. Use SCHEMA to scope down the query results to only the metrics that exactly match a list of dimensions, or to metrics that have no dimensions.

If you use a SCHEMA clause, it must contain at least one argument, and this first argument must be the metric namespace being queried. If you specify SCHEMA with only this namespace argument, the results are scoped down to only metrics that do not have any dimensions.

If you specify SCHEMA with additional arguments, the additional arguments after the namespace argument must be label keys. Label keys must be dimension names. If you specify one or more of these label keys, the results are scoped down to only those metrics that have that exact set of dimensions. The order of these label keys does not matter.

For example:

  • SELECT AVG(CPUUtilization) FROM "AWS/EC2" matches all CPUUtilization metrics in the AWS/EC2 namespace, no matter their dimensions, and returns a single aggregated time series.

  • SELECT AVG(CPUUtilization) FROM SCHEMA("AWS/EC2") matches only the CPUUtilization metrics in the AWS/EC2 namespace that do not have any dimensions defined.

  • SELECT AVG(CPUUtilization) FROM SCHEMA("AWS/EC2", InstanceId) matches only the CPUUtilization metrics that were reported to CloudWatch with exactly one dimension, InstanceId.

  • SELECT SUM(RequestCount) FROM SCHEMA("AWS/ApplicationELB", LoadBalancer, AvailabilityZone) matches only the RequestCount metrics that were reported to CloudWatch from AWS/ApplicationELB with exactly two dimensions, LoadBalancer and AvailabilityZone.

WHERE

Optional. Filters the results to only those metrics that match your specified expression using specific label values for one or more label keys. For example, WHERE InstanceType = 'c3.4xlarge' filters the results to only c3.4xlarge instance types, and WHERE InstanceType != 'c3.4xlarge' filters the results to all instance types except c3.4xlarge.

Label values must always be enclosed with single quotation marks.

Supported operators

The WHERE clause supports the following operators:

  • = Label value must match the specified string.

  • != Label value must not match the specified string.

  • AND Both conditions that are specified must be true to match. You can use multiple AND keywords to specify two or more conditions.

GROUP BY

Optional. Groups the query results into multiple time series, each one corresponding to a different value for the specified label key or keys. For example, using GROUP BY InstanceId returns a different time series for each value of InstanceId. Using GROUP BY ServiceName, Operation creates a different time series for each possible combination of the values of ServiceName and Operation.

With a GROUP BY clause, by default the results are ordered in alphabetical ascending order, using the sequence of labels specified in the GROUP BY clause. To change the order of the results, add an ORDER BY clause to your query.

Note

If some of the matching metrics don't include a specific label key specified in the GROUP BY clause, a null group named Other is returned. For example, if you specify GROUP BY ServiceName, Operation and some of the returned metrics don't include ServiceName as a dimension, then those metrics are displayed as having Other as the value for ServiceName.

ORDER BY

Optional. Specifies the order to use for the returned time series, if the query returns more than one time series. The order is based on the values found by the FUNCTION that you specify in the ORDER BY clause. The FUNCTION is used to calculate a single scalar value from each returned time series, and that value is used to determine the order.

You also specify whether to use ascending ASC or descending DESC order. If you omit this, the default is ascending ASC.

For example, adding an ORDER BY MAX() DESC clause orders the results by the maximum data point observed within the time range, in descending order: meaning that the time series that has the highest maximum data point is returned first.

The valid functions to use within an ORDER BY clause are AVG(), COUNT(), MAX(), MIN(), and SUM().

If you use an ORDER BY clause with a LIMIT clause, the resulting query is a "Top N" query. ORDER BY is also useful for queries that might return a large number of metrics, because each query can return no more than 500 time series. If a query matches more than 500 time series, and you use an ORDER BY clause, the time series are sorted and then the 500 time series that come first in the sort order are the ones that are returned.

LIMIT

Optional. Limits the number of time series returned by the query to the value that you specify. The maximum value that you can specify is 500, and a query that does not specify a LIMIT can also return no more than 500 time series.

Using a LIMIT clause with an ORDER BY clause gives you a "Top N" query.

What needs quotation marks or escape characters?

In a query, label values must always be surrounded with single quotation marks. For example, SELECT MAX(CPUUtilization) FROM "AWS/EC2" WHERE AutoScalingGroupName = 'my-production-fleet'.

Metric namespaces, metric names, and label keys that contain characters other than letters, numbers, and underscore (_) must be surrounded by double quote marks. For example, SELECT MAX("My.Metric").

If one of these contains a double quotation mark or single quotation mark itself (such as Bytes"Input"), you must escape each quotation mark with a backslash, as in SELECT AVG("Bytes\"Input\"").

If a metric namespace, metric name, or label key, contains a word that is a reserved keyword in Metrics Insights, these must also be enclosed in double quotation marks. For example, if you have a metric named LIMIT, you would use SELECT AVG("LIMIT"). It is also valid to enclose any namespace, metric name, or label in double quotation marks even if it does not include a reserved keyword.

For a complete list of reserved keywords, see Reserved keywords.

Building a rich query step by step

This section illustrates building a full example that uses all possible clauses, step by step.

We start with the following query, which aggregates all of the Application Load Balancer RequestCount metrics that are collected with both the dimensions LoadBalancer and AvailabilityZone.

SELECT SUM(RequestCount) FROM SCHEMA("AWS/ApplicationELB", LoadBalancer, AvailabilityZone)

Now, if we want to see metrics only from a specific load balancer, we can add a WHERE clause to limit the metrics returned to only those metrics where the value of the LoadBalancer dimension is app/load-balancer-1.

SELECT SUM(RequestCount) FROM SCHEMA("AWS/ApplicationELB", LoadBalancer, AvailabilityZone) WHERE LoadBalancer = 'app/load-balancer-1'

The preceding query aggregates the RequestCount metrics from all Availability Zones for this load balancer into one time series. If we want to see different time series for each Availability Zone, we can add a GROUP BY clause.

SELECT SUM(RequestCount) FROM SCHEMA("AWS/ApplicationELB", LoadBalancer, AvailabilityZone) WHERE LoadBalancer = 'app/load-balancer-1' GROUP BY AvailabilityZone

Next, we might want to order these results to see the highest values first. The following ORDER BY clause orders the time series in descending order, by the maximum value reported by each time series during the query time range:

SELECT SUM(RequestCount) FROM SCHEMA("AWS/ApplicationELB", LoadBalancer, AvailabilityZone) WHERE LoadBalancer = 'app/load-balancer-1' GROUP BY AvailabilityZone ORDER BY MAX() DESC

Finally, if we are primarily interested in a "Top N" type of query, we can use a LIMIT clause. This final example limits the results to only the time series with the five highest MAX values.

SELECT SUM(RequestCount) FROM SCHEMA("AWS/ApplicationELB", LoadBalancer, AvailabilityZone) WHERE LoadBalancer = 'app/load-balancer-1' GROUP BY AvailabilityZone ORDER BY MAX() DESC LIMIT 5