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Elasticsearch Guide [7.7] » REST APIs » Machine learning anomaly detection APIs » Get overall buckets API
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Get overall buckets APIedit

Retrieves overall bucket results that summarize the bucket results of multiple anomaly detection jobs.

Requestedit

GET _ml/anomaly_detectors/<job_id>/results/overall_buckets

GET _ml/anomaly_detectors/<job_id>,<job_id>/results/overall_buckets

GET _ml/anomaly_detectors/_all/results/overall_buckets

Prerequisitesedit

  • If the Elasticsearch security features are enabled, you must have monitor_ml, monitor, manage_ml, or manage cluster privileges to use this API. You also need read index privilege on the index that stores the results. The machine_learning_admin and machine_learning_user roles provide these privileges. See Security privileges and Built-in roles.

Descriptionedit

You can summarize the bucket results for all anomaly detection jobs by using _all or by specifying * as the <job_id>.

By default, an overall bucket has a span equal to the largest bucket span of the specified anomaly detection jobs. To override that behavior, use the optional bucket_span parameter. To learn more about the concept of buckets, see Buckets.

The overall_score is calculated by combining the scores of all the buckets within the overall bucket span. First, the maximum anomaly_score per anomaly detection job in the overall bucket is calculated. Then the top_n of those scores are averaged to result in the overall_score. This means that you can fine-tune the overall_score so that it is more or less sensitive to the number of jobs that detect an anomaly at the same time. For example, if you set top_n to 1, the overall_score is the maximum bucket score in the overall bucket. Alternatively, if you set top_n to the number of jobs, the overall_score is high only when all jobs detect anomalies in that overall bucket. If you set the bucket_span parameter (to a value greater than its default), the overall_score is the maximum overall_score of the overall buckets that have a span equal to the jobs' largest bucket span.

Path parametersedit

<job_id>
(Required, string) Identifier for the anomaly detection job. It can be a job identifier, a group name, a comma-separated list of jobs or groups, or a wildcard expression.

Request bodyedit

allow_no_jobs

(Optional, boolean) Specifies what to do when the request:

  • Contains wildcard expressions and there are no jobs that match.
  • Contains the _all string or no identifiers and there are no matches.
  • Contains wildcard expressions and there are only partial matches.

The default value is true, which returns an empty jobs array when there are no matches and the subset of results when there are partial matches. If this parameter is false, the request returns a 404 status code when there are no matches or only partial matches.

bucket_span
(Optional, string) The span of the overall buckets. Must be greater or equal to the largest bucket span of the specified anomaly detection jobs, which is the default value.
end
(Optional, string) Returns overall buckets with timestamps earlier than this time.
exclude_interim

(Optional, boolean) If true, the output excludes interim results. By default, interim results are included.

If any of the job bucket results within the overall bucket interval are interim results, the overall bucket results are interim results.

overall_score
(Optional, double) Returns overall buckets with overall scores greater than or equal to this value.
start
(Optional, string) Returns overall buckets with timestamps after this time.
top_n
(Optional, integer) The number of top anomaly detection job bucket scores to be used in the overall_score calculation. The default value is 1.

Response bodyedit

The API returns an array of overall bucket objects, which have the following properties:

bucket_span
(number) The length of the bucket in seconds. Matches the job with the longest bucket_span value.
is_interim
(boolean) If true, this is an interim result. In other words, the results are calculated based on partial input data.
jobs
(array) An array of objects that contain the max_anomaly_score per job_id.
overall_score
(number) The top_n average of the maximum bucket anomaly_score per job.
result_type
(string) Internal. This is always set to overall_bucket.
timestamp
(date) The start time of the bucket for which these results were calculated.

Examplesedit 

GET _ml/anomaly_detectors/job-*/results/overall_buckets
{
  "overall_score": 80,
  "start": "1403532000000"
}

In this example, the API returns a single result that matches the specified score and time constraints. The overall_score is the max job score as top_n defaults to 1 when not specified:

{
  "count": 1,
  "overall_buckets": [
    {
      "timestamp" : 1403532000000,
      "bucket_span" : 3600,
      "overall_score" : 80.0,
      "jobs" : [
        {
          "job_id" : "job-1",
          "max_anomaly_score" : 30.0
        },
        {
          "job_id" : "job-2",
          "max_anomaly_score" : 10.0
        },
        {
          "job_id" : "job-3",
          "max_anomaly_score" : 80.0
        }
      ],
      "is_interim" : false,
      "result_type" : "overall_bucket"
    }
  ]
}

The next example is similar but this time top_n is set to 2:

GET _ml/anomaly_detectors/job-*/results/overall_buckets
{
  "top_n": 2,
  "overall_score": 50.0,
  "start": "1403532000000"
}

Note how the overall_score is now the average of the top 2 job scores:

{
  "count": 1,
  "overall_buckets": [
    {
      "timestamp" : 1403532000000,
      "bucket_span" : 3600,
      "overall_score" : 55.0,
      "jobs" : [
        {
          "job_id" : "job-1",
          "max_anomaly_score" : 30.0
        },
        {
          "job_id" : "job-2",
          "max_anomaly_score" : 10.0
        },
        {
          "job_id" : "job-3",
          "max_anomaly_score" : 80.0
        }
      ],
      "is_interim" : false,
      "result_type" : "overall_bucket"
    }
  ]
}
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