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Concepts and Terminology

  • Aggregators: A mechanism for combining records during realtime incremental indexing, Hadoop batch indexing, and in queries.
  • DataSource: A table-like view of data; specified in a “specFile” and in a query.
  • Granularity: The time interval corresponding to aggregation by time.
    • indexGranularity: specifies the granularity used to bucket timestamps within a segment.
    • segmentGranularity: specifies the granularity of the segment, i.e. the amount of time a segment will represent
  • Segment: A collection of (internal) records that are stored and processed together.
  • Shard: A sub-partition of the data in a segment. It is possible to have multiple segments represent all data for a given segmentGranularity.
  • specFile: is specification for services in JSON format; see Realtime and Batch-ingestion