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LearnDefend
Elastic Security & the Stack
TheoryBeginner10 minSIEM OperationLog Analysis

Discover, the Time Picker and the Histogram

What is it?

Discover is where you explore raw events: a data view, a KQL bar, a time picker, and a histogram of event counts over the selected window. Every search happens inside the chosen time range — nothing outside it is returned.

Why it matters

The time range is the single most common reason a search 'finds nothing'. The evidence is usually just outside the window. The histogram also lets you see when activity spiked before you even filter.

Where you see it

Top-right time picker: 'Last 15 minutes', 'Last 24 hours', or an absolute range. The histogram bars show counts per interval; clicking a bar zooms the range to that spike.

What normal looks like

A time range wide enough to contain the event, and a histogram whose shape matches normal business rhythm — busy in the day, quiet at night.

What suspicious looks like

A histogram spike at an odd hour, or activity that continues flat through the night when humans are gone. But first make sure the empty result is not simply a too-narrow time range.

How analysts investigate

Set a time range you are confident contains the event (widen when unsure), read the histogram for spikes, click a spike to zoom, then apply KQL to narrow to the events that answer the question.

Common beginner mistakes

  • Concluding 'nothing happened' when the time picker was set narrower than the incident.
  • Ignoring the histogram, which often shows the spike before any filtering.

Every search lives inside the time range

  [ KQL: event.outcome:failure ]     [ Time: Last 24 hours ▾ ]
  histogram (count per hour):
    ▁▁▂▂▃▃▅▇█ ... ▁▁            ← a spike at 02:00 when the office is empty
  click the 02:00 bar → range zooms → Discover lists just those events
  empty result?  FIRST suspect the time range, not the absence of evidence
The time picker bounds every query; the histogram reveals spikes before you filter.

Quick check

Your KQL query returns zero documents. What is the FIRST thing to check?

A quick self-check — it doesn't affect your XP or progress.

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