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 scanNested loop joinSort merge joinNOT INGROUP BYHash joinSELECT DISTINCTUNION and UNION ALLAggregationPL/SQL functions called from SQLORDER BYDDL:CREATE TABLE AS SELECTCREATE INDEXRebuild indexMove partitionSplit partitionDML:UPDATE   on partitioned tableDELETE   on partitioned tableMERGE    on partitioned tableINSERT … SELECTEnable constraint (the table scan is parallelized)Star transformation