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在非分区索引上使用并行提示:
如下全表扫描并行提示可以生效:
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完成,select /* +,完整(部门),并行(dept 2), */deptno 得到部门; Execution 计划 ---------------------------------------------------------- Plan hash 值:587379989 ------------------------------------------------------------------------------------------------------------- | |,Id 还以为;Operation ,,,, |,名字|,行|,Bytes |, Cost (% CPU) |,时间|,,,,TQ , | in - out |, PQ Distrib | -------------------------------------------------------------------------------------------------------------- |,,,0,|,SELECT STATEMENT ,,,, | |,,,,, 4, |,,,, 12, |,,,,, 2,,, (0) |, 00:00:01 |, | |,,,, | |,,,1,|,,PX COORDINATOR ,,,,, | | | |,,,,, | |, | |,,,, | |,,,2,|,,,PX SEND QC (随机)|,:TQ10000 |,,,,, 4, |,,,, 12, |,,,,, 2,,, (0) |, 00:00:01 |,, Q1, 00, |, P→S |, QC (RAND), | |,,,3,|,,,,PX BLOCK ITERATOR | |,,,,, 4, |,,,, 12, |,,,,, 2,,, (0) |, 00:00:01 |,, Q1, 00, |, PCWC |,,,, | |,,,4,|,,,,,TABLE ACCESS 全部|,部门|,,,,,4,|,,,,12,|,,,,,2,,,(0)|,00:00:01 |,, Q1, 00, |, PCWP |,,,, | -------------------------------------------------------------------------------------------------------------- 统计数据 ---------------------------------------------------------- ,11 recursive 调用 ,,0,db block 5,才能consistent 得到 6,才能physical 读取 0,才能redo 大小 594年,,bytes sent  via SQL * Net 用客户端 523年,,bytes received  via SQL * Net 得到客户 2,才能,SQL * Net roundtrips /得到客户 ,,0,sorts (内存) ,,0,sorts (磁盘) ,,4,rows 处理
非分区索引使用并行提示无效:
完成,select /* +,指数(dept pk_dept),并行(dept 2), */deptno 得到部门; Execution 计划 ---------------------------------------------------------- Plan hash 值:2913917002 ---------------------------------------------------------------------------- | |,Id 还以为;Operation |, Name ,,, |, Rows , |, Bytes |, Cost (% CPU) |, Time , | ---------------------------------------------------------------------------- |,,,0,|,SELECT STATEMENT |,,, |, 4, | 12, |, 1,,, (0) |, 00:00:01 | |,,,1,|,,INDEX FULL SCAN |, PK_DEPT |, 4, | 12, |, 1,,, (0) |, 00:00:01 | ---------------------------------------------------------------------------- 统计数据 ---------------------------------------------------------- ,62年,recursive 调用 ,,0,db block ,59,consistent 0,才能physical 读取 0,才能redo 大小 594年,,bytes sent  via SQL * Net 用客户端 523年,,bytes received  via SQL * Net 得到客户 2,才能,SQL * Net roundtrips /得到客户 7,才能,sorts (内存) ,,0,sorts (磁盘) ,,4,rows 处理
use_hash中指定被驱动表错误,提示无效:
完成,select /* +, use_hash (t2), */, t1.empno, t1.ename, t2.loc 得到emp t1, dept t2 where t1.deptno=t2.deptno 以及t2.loc=爸ゼ痈纭? 6,rows 选中。 Execution 计划 ---------------------------------------------------------- Plan hash 值:844388907 null null null null null null null null null null null null null null null null null null null null null null null null null null null null null null null null null甲骨文提示学习之二(忽略暗示的情形)