For the purpose of getting this API consumed by our UI, returning
overall buckets that match the job's largest `bucket_span` can
result in too much data. The UI only ever displays a few buckets
in the swimlane. Their span depends on the time range selected and
the screen resolution, but it will only ever be a relatively
low number.
This PR adds the ability to aggregate overall buckets in a user
specified `bucket_span`. That `bucket_span` may be equal or
greater to the largest job's `bucket_span`. The `overall_score`
of the result overall buckets is the max score of the
corresponding overall buckets with a span equal to the job's
largest `bucket_span`.
The implementation is now chunking the bucket requests
as otherwise the aggregation would fail when too many buckets
are matching.
Original commit: elastic/x-pack-elasticsearch@981f7a40e5
Adds the GET overall_buckets API.
The REST end point is: GET
/_xpack/ml/anomaly_detectors/job_id/results/overall_buckets
The API returns overall bucket results. An overall bucket
is a summarized bucket result over multiple jobs.
It has the `bucket_span` of the longest job's `bucket_span`.
It also has an `overall_score` that is the `top_n` average of the
max anomaly scores per job.
relates elastic/x-pack-elasticsearch#2693
Original commit: elastic/x-pack-elasticsearch@ba6061482d
lcawley
Dimitris Athanasiou