2.filter --过滤,如not in、min函数等容易产生 Has a number of different meanings, used to indicate partition elimination, may also indicate an actual filter step where one row source is filtering, another, functions such as min may introduce filter steps into query plans. 3.view --视图,大都...
Introduced in 7.3 and requires V733_PLANS_ENABLED=TRUE and CBO, may be hinted using INDEX_FFS hint, uses multiblock i/o, can be executed in parallel, can be used to access second column of concatenated indexes. This is because we are selecting all of the index. ...
('plan_table',null,'typical -cost -bytes')); Figure 6: Customized TYPICAL plan with suppressed options COST and BYTES The Note Section In addition to the plan and the predicate information, the DBMS_XPLAN package displays additional information in the NOTE section, such as when dynamic ...
Redshift EXPLAIN is used for checking and seeing the complete flow of execution steps that will be performed while executing the query that you have mentioned in the explain command itself. We can check the performance and try to make our queries and the clauses that we are using in it suc...
SQL coding help Query 1: Which guest(s) (only list the guestNo) have stayed in both hotelNo 2 and hotelNo 4? Query 2: which hotels (only list the hotel number) do not have family rooms? Query 3: Wh What is the use of force ...
The statement in Example 12-4 displays the execution plans. Example 12-4 Statement to display the EXPLAIN PLAN SELECT PLAN_TABLE_OUTPUT FROM TABLE(DBMS_XPLAN.DISPLAY(NULL, 'statement_id','BASIC')); Examples of the output from this statement are shown in Example 12-5 and Example 12-6. ...
SQL> select * from table(dbms_xplan.display); PLAN_TABLE_OUTPUT --- --- Plan hash value: 2498281325 --- --- | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| ---
1.setautotraceon2.explain planforsql语句;selectplan_table_outputfromtable(dbms_xplan.display());3.通过第3方工具,如plsql developer(f5查看执行计划)、toad等; 三、看懂执行计划 1.执行计划中字段解释 SQL> select * from scott.emp a,scott.emp b where a.empno=b.mgr; ...
('plan_table',null,'typical -cost -bytes')); Figure 6: Customized TYPICAL plan with suppressed options COST and BYTES The Note Section In addition to the plan and the predicate information, the DBMS_XPLAN package displays additional information in the NOTE section, such as when dynamic ...
select plan_table_output from table(dbms_xplan.display()); 3.通过第3方工具,如plsql developer(f5查看执行计划)、toad等; 三、看懂执行计划 1.执行计划中字段解释 SQL> select * from scott.emp a,scott.emp b wherea.empno=b.mgr; 已选择13行。