36 lines
2.3 KiB
Markdown
36 lines
2.3 KiB
Markdown
---
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{
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"title": "Doris base concept",
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"language": "en"
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}
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---
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# Doris base concept
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- FE: Frontend, the front-end node of Doris. It is mainly responsible for receiving and returning client requests, metadata, cluster management, and query plan generation.
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- BE: Backend, the backend node of Doris. Mainly responsible for data storage and management, query plan execution and other work.
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- Broker: Broker is a stateless process. It is mainly to help Doris access external data sources such as data on HDFS in a Unix-like file system interface. For example, it is used in data import or data export operations.
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- Tablet: Tablet is the actual physical storage unit of a table. A table is stored in units of Tablet in the distributed storage layer composed of BE after partitioning and bucketing. Each Tablet includes meta information and several consecutive RowSets. .
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- Rowset: Rowset is a data collection of a data change in the tablet, and the data change includes data import, deletion, and update. Rowset records by version information. A version is generated for each change.
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- Version: It consists of two attributes, Start and End, and maintains the record information of data changes. Usually used to indicate the version range of Rowset, after a new import, a Rowset with equal Start and End is generated, and a Rowset version with a range is generated after Compaction.
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- Segment: Indicates the data segment in the Rowset. Multiple Segments form a Rowset.
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- Compaction: The process of merging consecutive versions of Rowset is called Compaction, and the data will be compressed during the merging process. |