Oracle中可被并行化执行的SQL操作
并不是所有的SQL operations都是可并行化的;不少人认为sort merge join这种排序合并操作是不能并行化的,这显示是一种错误的认识。有了这样一个列表你就可以更好地理解Oracle中的Parallel Execution了:
Parallel Query: Table scan Nested loop join Sort merge join NOT IN GROUP BY Hash join SELECT DISTINCT UNION and UNION ALL Aggregation PL/SQL functions called from SQL ORDER BY DDL: CREATE TABLE AS SELECT CREATE INDEX Rebuild index Move partition Split partition DML: UPDATE on partitioned table DELETE on partitioned table MERGE on partitioned table INSERT … SELECT Enable constraint (the table scan is parallelized) Star transformation
posted on 2013-03-19 00:46 Oracle和MySQL 阅读(377) 评论(0) 编辑 收藏 举报