首页>
外国专利>
Dynamic rebuilding of query execution trees and reselection of query execution operators
Dynamic rebuilding of query execution trees and reselection of query execution operators
展开▼
机译:动态重建查询执行树和重新选择查询执行运算符
展开▼
页面导航
摘要
著录项
相似文献
摘要
A database engine receives a query and parses the query to form a first intermediate query. The engine compiles the first intermediate query to form a first executable plan that includes in-memory operators that execute within memory without swapping to secondary memory. While executing a first in-memory operator in the first executable plan, the engine detects insufficient memory and aborts execution of the first executable plan. The engine optimizes the first intermediate query to form a second intermediate query, and compiles the second intermediate query to form a second executable plan. The second plan includes spooling operators that execute within fixed memory budgets and are configured to swap to the secondary memory when needed. The engine executes the second executable plan, including the spooling operators, to retrieve results from the database that are responsive to the query. The engine then returns the retrieved results.
展开▼