Lens for drag-and-drop analysis in Elasticsearch - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Lens drag-and-drop configuration?

Given a Lens visualization in Elasticsearch where you drag the "bytes" field to the Y-axis and the "extension.keyword" field to the X-axis, what will the chart display?

Elasticsearch

Lens config:
- Y-axis: Sum of bytes
- X-axis: Terms of extension.keyword

Data sample:
{
  "extension": "jpg",
  "bytes": 1000
},
{
  "extension": "png",
  "bytes": 2000
},
{
  "extension": "jpg",
  "bytes": 1500
}

A A pie chart showing count of documents per extension without bytes aggregation

B A line chart showing average bytes per document regardless of extension

C A bar chart showing total bytes for each file extension, e.g., jpg: 2500, png: 2000

D A table listing each document with bytes and extension fields

💡 Hint

Think about what happens when you drag a numeric field to the Y-axis and a keyword field to the X-axis in Lens.

Dragging bytes to the Y-axis with aggregation sum and extension.keyword to the X-axis with terms aggregation creates a bar chart showing total bytes per extension.

🧠 Conceptual

intermediate

Which Lens feature allows you to change the aggregation type for a dragged field?

In Elasticsearch Lens, after dragging a field to an axis, how can you change the aggregation method (e.g., from sum to average)?

A By clicking the field on the axis and selecting the aggregation from the dropdown menu

B By editing the Elasticsearch query manually in the Lens interface

C By dragging the field again to the other axis

D By changing the index pattern in the Lens settings

💡 Hint

Look for interactive controls on the axis field after dragging.

Lens lets you click on the field on the axis to open a menu where you can select aggregation types like sum, average, min, max, etc.

🔧 Debug

advanced

Why does this Lens visualization show no data after dragging fields?

You dragged timestamp to the X-axis and bytes to the Y-axis in Lens, but the chart shows no data. What is the most likely cause?

Elasticsearch

Lens config:
- X-axis: Date histogram on timestamp
- Y-axis: Sum of bytes

Data sample:
{
  "timestamp": "2023-01-01T00:00:00Z",
  "bytes": 1000
}

Index pattern uses a different time field named "@timestamp".

A Lens requires a keyword field on the X-axis, not a date field

B The index pattern's time field is different from the dragged timestamp field, so Lens cannot filter data by time

C The date histogram interval is too large to show data

D The bytes field is not numeric, so sum aggregation fails silently

💡 Hint

Check the index pattern's configured time field and the field used in the visualization.

If the index pattern's time field is different from the field used in the date histogram, Lens cannot filter data by time range, resulting in no data shown.

📝 Syntax

advanced

Which Lens drag-and-drop configuration will produce a stacked bar chart by default?

In Lens, you want to create a stacked bar chart showing total bytes per extension, split by the geo.src field. Which drag-and-drop setup achieves this?

A Y-axis: Terms of geo.src.keyword; X-axis: Sum of bytes; Break down by: Terms of extension.keyword

B Y-axis: Count; X-axis: Terms of extension.keyword; Break down by: Terms of geo.src.keyword

C Y-axis: Sum of bytes; X-axis: Terms of geo.src.keyword; Break down by: Terms of extension.keyword

D Y-axis: Sum of bytes; X-axis: Terms of extension.keyword; Break down by: Terms of geo.src.keyword

💡 Hint

Think about which axis shows the main grouping and which field breaks down the bars.

Dragging bytes to Y-axis with sum aggregation, extension.keyword to X-axis, and geo.src.keyword to 'Break down by' creates stacked bars grouped by extension and split by geo.src.

🚀 Application

expert

How to create a Lens visualization that shows average bytes per day for top 3 extensions?

You want a Lens chart that shows the average bytes per day on the Y-axis, with the X-axis as a date histogram on @timestamp, but only for the top 3 file extensions by count. How do you configure Lens?

A Y-axis: Average of bytes; X-axis: Date histogram on @timestamp; Use 'Break down by' with extension.keyword limited to 3 terms

B Y-axis: Sum of bytes; X-axis: Date histogram on @timestamp; Use 'Break down by' with extension.keyword limited to 3 terms

C Y-axis: Average of bytes; X-axis: Terms of extension.keyword limited to 3; Use 'Break down by' with date histogram on @timestamp

D Y-axis: Average of bytes; X-axis: Date histogram on @timestamp; Add a filter to include only top 3 extensions by terms aggregation on extension.keyword

💡 Hint

Consider how to limit the number of extensions shown and how to arrange date histogram and terms fields.

Setting Y-axis to average bytes, X-axis to date histogram on @timestamp, and 'Break down by' to extension.keyword limited to top 3 terms shows average bytes per day split by top 3 extensions.