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User guide

Field dictionary

Scan an index: which fields it has, their types, cardinality and sample values. Confirm field names before writing a query or a rule.

The field dictionary reads the index mapping plus a sample of documents and shows the fields and values the cluster actually has, independent of the ECS spec. Smart query and detection rules use the same scan internally. Every edition.

Scanning

Field dictionary

Pick an index (wildcards allowed, e.g. logs-nginx.*) and click "Scan index". Results are cached for 5 minutes (RST_FIELD_DICT_CACHE_TTL_S).

Scan overview

Scan overview

CardMeaning
DocumentsHow many indices matched, how many documents
Fields scannedHow many the mapping declares, how many the sample saw; large indices scanned partially are marked
Empty fieldsIn the mapping but never seen in the sample; avoid them in rules
Highest-cardinality fieldMost distinct values, usually IDs, timestamps, message bodies
Type mixShare of keyword / text / date / ip / long …

Field table

Field table

One row per field: name, type, estimated distinct values, sample values (most frequent first).

  • Filter by name, filter by type.
  • Click a sample value to copy it as field:"value", ready to paste into a query or rule.
  • Row actions: "Insert into query" takes the field to Smart query; "Aggregate by X, top 10" builds a statistics question in one click.

Typical uses

  • Confirm field names before writing a detection intent: event.action or event.type, value login_failure or failed.
  • Check sample values when a smart query finds nothing: the log says ERROR, not error.
  • Judge whether an index is worth onboarding: many empty fields or odd cardinalities point at a collector mapping problem.

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