mirror of https://github.com/apache/druid.git
15 lines
961 B
Markdown
15 lines
961 B
Markdown
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layout: doc_page
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Concepts and Terminology
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* **Aggregators**: A mechanism for combining records during realtime incremental indexing, Hadoop batch indexing, and in queries.
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* **DataSource**: A table-like view of data; specified in a "specFile" and in a query.
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* **Granularity**: The time interval corresponding to aggregation by time.
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* **indexGranularity**: specifies the granularity used to bucket timestamps within a segment.
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* **segmentGranularity**: specifies the granularity of the segment, i.e. the amount of time a segment will represent
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* **Segment**: A collection of (internal) records that are stored and processed together.
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* **Shard**: A sub-partition of the data in a segment. It is possible to have multiple segments represent all data for a given segmentGranularity.
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* **specFile**: is specification for services in JSON format; see [Realtime](Realtime.html) and [Batch-ingestion](Batch-ingestion.html)
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