2.3 KiB
2.3 KiB
title, language
| title | language |
|---|---|
| Doris base concept | en |
Doris base concept
- 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.
- BE: Backend, the backend node of Doris. Mainly responsible for data storage and management, query plan execution and other work.
- 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.
- 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. .
- 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.
- 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.
- Segment: Indicates the data segment in the Rowset. Multiple Segments form a Rowset.
- Compaction: The process of merging consecutive versions of Rowset is called Compaction, and the data will be compressed during the merging process.