For example: SELECT /*+ INDEX (employees emp_department_ix)*/ employee_id, department_id FROM employees WHERE department_id > 50; INDEX_FFS Hint For example: SELECT /*+ INDEX_FFS(e emp_name_ix) */ first_name FROM employees e; 驱动表的选择 LEADING Hint SELECT /*+ LEADING(e j) */...
INDEX_COMBINEIf no indexes are given as arguments for the INDEX_COMBINE hint, the optimizer will use on the table whatever boolean combination of bitmap indexes has the best cost estimate. If certain indexes are given as arguments, the optimizer will try to use some boolean combination of thos...
INDEX_COMBINEIf no indexes are given as arguments for the INDEX_COMBINE hint, the optimizer will use on the table whatever boolean combination of bitmap indexes has the best cost estimate. If certain indexes are given as arguments, the optimizer will try to use some boolean combination of thos...
4、/*+ INDEX_COMBINE*/ 为指定表选择位图访问路经,如果INDEX_COMBINE中没有提供作为参数的索引,将选择出位图索引的布尔组合方式. SELECT /*+INDEX_COMBINE(BSEMPMS SAL_BMI HIREDATE_BMI) */ * FROM BSEMPMS WHERE SAL<5000000 AND HIREDATE 5、/*+ INDEX_JOIN(TABLE INDEX_NAME1 INDEX_NAME2) */ 当...
Description: The BATCH_TABLE_ACCESS_BY_ROWID hint instructs the optimizer to retrieve a few rowids from the index, then access the rows in data block order, to reduce accessing data block times . SQL?? HelloDBA.com> alter session set "_optimizer_batch_table_access_by_rowid"=false; Hello...
INDEX FULL SCAN CBOTAB1 [ANALYZED] Cost=151 Card=10000 Bytes=100000 The TABLE_NAME is mandatory in the hint. In the following example the TABLE_NAME was omitted so the index was not used. SQL> explain plan for select /*+ index() */ col1 from cbotab; ...
Of course, if large access counts are happening fairly frequently you can raise the question – does this look an appropriate result for the table or index, or does it hint at an index that is used when it should not be, or an index that needs to be refined (e.g. by the addition ...
index maintenance, 22-8temporary segments, 22-9 See also parallel SQL parallel execution servers direct-load INSERT, 22-3 PARALLEL hint, 23-17 parallelization rules, 23-20 UPDATE and DELETE, 23-22 parallel query, 23-28 bitmap indexes, 10-35 functions, 23-47 index-organized ...
I'm sure some of you are now tempted to reach for the index hint. This instructs the database to use the index. This can be useful for seeing if it really is more efficient than the plan the optimizer chose instead.But I strongly discourage you from using these in your production SQL...
index fast full scan --索引快速全局扫描，不带order by情况下常发生 Scans all the block in the index, Rows are not returned in sorted order, 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 ...