AT:

• similar to list/map report limits implemented with OPT-2126 we need to limit the number of data histogram buckets
• the max bucket limit to apply is defined by es.settings.aggregationBucketLimit
• there are two cases to cover:
  1. user defined startDate-/endDate-/evaluationDateFilter is present
     • given the group by unit & the filter enforce a limit of configured max bucket limit from the endDate of the filter
  2. no startDate-/endDate-/evaluationDateFilter present
     • given the group by unit add a default startDate/evaluationDateFilter that results in the number of maximum buckets
• whenever the limiting was applied to an evaluation and not all entities of the original report filter (or not defined filter) were contributing to the result the result.isComplete flag has to be set to false

Notes:

• for date histograms the limitation has to happen before the elasticsearch query gets executed by either:
  • modifying the filter query
  • adding a filter aggregation (might be less intrusive as no modification to the base query required + we could compare the doc count of it with that of the main query to decide on setting result.isComplete )
• in case of endDateFilters we apply the same limiting logic as for startDateFilters assuming the resulting groupByStartDate bucket count is usually close to the desired maximum buckets count due to the duration being normally distributed