Tutorial: Run a query with an aggregation function

You can use aggregation functions with the stats command and as arguments for other functions. In this tutorial, you run a query command that counts the number of log events containing a specified field. The query command returns a total count that's grouped by the specified field's value or values. For more information about aggregation functions, see Supported operations and functions in the Amazon CloudWatch Logs User Guide.

To run a query with an aggregation function

1. Open the CloudWatch console at https://console.aws.amazon.com/cloudwatch/.

2. In the navigation pane, choose Logs, and then choose Logs Insights.

3. In the Select log group(s) drop down, choose one or more log groups to query.

   If this is a monitoring account in CloudWatch cross-account observability, you can select log groups in the source accounts as well as the monitoring account. A single query can query logs from different accounts at once.

   You can filter the log groups by log group name, account ID, or account label.

   When you select a log group, CloudWatch Logs Insights automatically detects data fields in the log group if it is a Standard class log group. To see discovered fields, select the Fields menu near the top right of the page.

4. Delete the default query in the query editor, and enter the following command:

   stats count(*) by fieldName

5. Replace fieldName with a discovered field from the Fields menu.

   The Fields menu is located at the top right of the page and displays all of the discovered fields that CloudWatch Logs Insights detects in your log group.

6. Choose Run to view the query results.

   The query results show the number of records in your log group that match the query command and the total count that's grouped by the specified field's value or values.