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| |
| # 查询引擎 |
| |
| <img style="width:100%; max-width:800px; max-height:600px; margin-left:auto; margin-right:auto; display:block;" src="https://user-images.githubusercontent.com/37140360/110063320-e4678f00-7da5-11eb-8d1b-6c804c1846ba.png"> |
| |
| ## 设计思想 |
| |
| 查询引擎负责所有用户命令的解析、生成计划、交给对应的执行器、返回结果集。 |
| |
| ## 相关类 |
| |
| * org.apache.iotdb.db.service.TSServiceImpl |
| |
| IoTDB 服务器端 RPC 实现，与客户端进行直接交互。 |
| |
| * org.apache.iotdb.db.qp.Planner |
| |
| 解析 SQL，生成逻辑计划，逻辑优化，生成物理计划。 |
| |
| * org.apache.iotdb.db.qp.executor.PlanExecutor |
| |
| 分发物理计划给对应的执行器，主要包括以下四个具体的执行器。 |
| |
| * MManager: 元数据操作 |
| * StorageEngine: 数据写入 |
| * QueryRouter: 数据查询 |
| * LocalFileAuthorizer: 权限操作 |
| |
| * org.apache.iotdb.db.query.dataset.* |
| |
| 分批构造结果集返回给客户端，包含部分查询逻辑。 |
| |
| ## 查询流程 |
| |
| * SQL 解析 |
| * 生成逻辑计划 |
| * 生成物理计划 |
| * 构造结果集生成器 |
| * 分批返回结果集 |
| |
| ## 相关文档 |
| |
| * [查询计划生成器](../QueryEngine/Planner.md) |
| * [计划执行器](../QueryEngine/PlanExecutor.md) |
