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