Date histogram in Elasticsearch - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a date histogram in Elasticsearch?

A date histogram is an aggregation that groups documents into buckets based on intervals of time, like days, months, or years. It helps analyze data trends over time.

beginner

Which field type is required for a date histogram aggregation?

The field must be of a date type in Elasticsearch to use a date histogram aggregation.

intermediate

What does the calendar_interval parameter do in a date histogram?

It sets the time interval for buckets using calendar-aware units like 'day', 'month', or 'year', which respect calendar boundaries.

intermediate

How does fixed_interval differ from calendar_interval in date histograms?

fixed_interval uses fixed time spans like '1h' or '30m' ignoring calendar boundaries, while calendar_interval respects calendar units.

intermediate

What is the purpose of the min_doc_count parameter in a date histogram aggregation?

It controls whether buckets with zero documents are included. Setting min_doc_count to 0 includes empty buckets for continuous time intervals.

Which parameter defines the time interval for buckets in a date histogram?

A field

B calendar_interval

C min_doc_count

D size

The calendar_interval parameter sets the time interval for buckets, like 'day' or 'month'.

What type must the field be for a date histogram aggregation?

A date

B keyword

C integer

D text

The field must be of type date to use date histogram aggregation.

What happens if you set min_doc_count to 0 in a date histogram?

A Only one bucket is created

B Buckets with zero documents are excluded

C Aggregation fails

D Buckets with zero documents are included

Setting min_doc_count to 0 includes empty buckets for continuous intervals.

Which interval type ignores calendar boundaries?

A calendar_interval

B min_doc_count

C fixed_interval

D field

fixed_interval uses fixed time spans ignoring calendar boundaries.

What is the main use of a date histogram aggregation?

A Group documents by time intervals

B Group documents by numeric range

C Group documents by text content

D Sort documents alphabetically

Date histogram groups documents into time-based buckets to analyze trends.

Explain how a date histogram aggregation works and when you would use it.

Think about how you might group events by days or months to see patterns.

Describe the difference between calendar_interval and fixed_interval in date histograms.

Consider how months vary in length but fixed intervals do not.