索引优化系列十三--分区表各类聚合优化玄机

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-- 范围分区示例

drop table range_part_tab purge;

--注意,此分区为范围分区


--例子1

create table range_part_tab (id number,deal_date date,area_code number,nbr number,contents varchar2(4000))

partition by range (deal_date)

(

partition p_201301 values less than (TO_DATE('2013-02-01','YYYY-MM-DD')),

partition p_201302 values less than (TO_DATE('2013-03-01',

partition p_201303 values less than (TO_DATE('2013-04-01',

partition p_201304 values less than (TO_DATE('2013-05-01',

partition p_201305 values less than (TO_DATE('2013-06-01',

partition p_201306 values less than (TO_DATE('2013-07-01',

partition p_201307 values less than (TO_DATE('2013-08-01',

partition p_201308 values less than (TO_DATE('2013-09-01',

partition p_201309 values less than (TO_DATE('2013-10-01',

partition p_201310 values less than (TO_DATE('2013-11-01',

partition p_201311 values less than (TO_DATE('2013-12-01',

partition p_201312 values less than (TO_DATE('2014-01-01',

partition p_201401 values less than (TO_DATE('2014-02-01',

partition p_201402 values less than (TO_DATE('2014-03-01',

partition p_max values less than (maxvalue)

)

;


alter table RANGE_PART_TAB modify nbr not null;

--以下是插入2013年一整年日期随机数和表示福建地区号含义(591到599)的随机数记录,共有10万条,如下:

insert into range_part_tab (id,deal_date,area_code,nbr,contents)

select rownum,

to_date( to_char(sysdate-365,'J')+TRUNC(DBMS_RANDOM.VALUE(0,365)),'J'),

ceil(dbms_random.value(591,599)),

ceil(dbms_random.value(18900000001,18999999999)),

rpad('*',400,'*')

from dual

connect by rownum <= 100000;

commit;




--以下是插入2014年一整年日期随机数和表示福建地区号含义(591到599)的随机数记录,共有10万条,如下:

insert into range_part_tab (id,

to_date( to_char(sysdate,'*')

from dual

connect by rownum <= 100000;

commit;




create index idx_part_id on range_part_tab (id) ;

create index idx_part_nbr on range_part_tab (nbr) local;


--统计信息系统一般会自动收集,这只是首次建成表后需要操作一下,以方便测试

exec dbms_stats.gather_table_stats(ownname => 'LJB',tabname => 'RANGE_PART_TAB',estimate_percent => 10,method_opt=> 'for all indexed columns',cascade=>TRUE) ;



set autotrace on

set linesize 1000



select max(nbr) max_nbr from range_part_tab partition(p_201305);

执行计划

------------------------------------------------------------------------------------------------------------

| Id | Operation | Name | Rows | Bytes | Cost (%cpu)| Time | Pstart| Pstop |

------------------------------------------------------------------------------------------------------------

| 0 | SELECT STATEMENT | | 1 | 8 | 2 (0)| 00:00:01 | | |

| 1 | SORT AGGREGATE | | 1 | 8 | | | | |

| 2 | PARTITION RANGE SINGLE | | 1 | 8 | 2 (0)| 00:00:01 | 5 | 5 |

| 3 | INDEX FULL SCAN (MIN/MAX)| IDX_PART_NBR | 1 | 8 | 2 (0)| 00:00:01 | 5 | 5 |

------------------------------------------------------------------------------------------------------------

统计信息

----------------------------------------------------------

0 recursive calls

0 db block gets

2 consistent gets


select max(nbr) max_nbr

from range_part_tab

where deal_date >= TO_DATE('2013-05-01','YYYY-MM-DD')

and deal_date < TO_DATE('2013-06-01','YYYY-MM-DD');

执行计划

----------------------------------------------------------------------------------------------------------

| Id | Operation | Name | Rows | Bytes | Cost (%cpu)| Time | Pstart| Pstop |

----------------------------------------------------------------------------------------------------------

| 0 | SELECT STATEMENT | | 1 | 17 | 170 (0)| 00:00:03 | | |

| 1 | SORT AGGREGATE | | 1 | 17 | | | | |

| 2 | PARTITION RANGE SINGLE| | 22 | 374 | 170 (0)| 00:00:03 | 5 | 5 |

| 3 | TABLE ACCESS FULL | RANGE_PART_TAB | 22 | 374 | 170 (0)| 00:00:03 | 5 | 5 |

----------------------------------------------------------------------------------------------------------

统计信息

----------------------------------------------------------

0 recursive calls

0 db block gets

568 consistent gets









select count(*) max_nbr from range_part_tab partition(p_201305);

执行计划

------------------------------------------------------------------------------------------------

| Id | Operation | Name | Rows | Cost (%cpu)| Time | Pstart| Pstop |

------------------------------------------------------------------------------------------------

| 0 | SELECT STATEMENT | | 1 | 8 (0)| 00:00:01 | | |

| 1 | SORT AGGREGATE | | 1 | | | | |

| 2 | PARTITION RANGE SINGLE| | 8716 | 8 (0)| 00:00:01 | 5 | 5 |

| 3 | INDEX FAST FULL SCAN | IDX_PART_NBR | 8716 | 8 (0)| 00:00:01 | 5 | 5 |

------------------------------------------------------------------------------------------------

统计信息

----------------------------------------------------------

0 recursive calls

0 db block gets

29 consistent gets


select count(*) max_nbr

from range_part_tab

where deal_date >= TO_DATE('2013-05-01','YYYY-MM-DD');

执行计划

----------------------------------------------------------------------------------------------------------

| Id | Operation | Name | Rows | Bytes | Cost (%cpu)| Time | Pstart| Pstop |

----------------------------------------------------------------------------------------------------------

| 0 | SELECT STATEMENT | | 1 | 9 | 170 (0)| 00:00:03 | | |

| 1 | SORT AGGREGATE | | 1 | 9 | | | | |

| 2 | PARTITION RANGE SINGLE| | 22 | 198 | 170 (0)| 00:00:03 | 5 | 5 |

| 3 | TABLE ACCESS FULL | RANGE_PART_TAB | 22 | 198 | 170 (0)| 00:00:03 | 5 | 5 |

----------------------------------------------------------------------------------------------------------

统计信息

----------------------------------------------------------

0 recursive calls

0 db block gets

568 consistent gets


select sum(nbr) max_nbr from range_part_tab partition(p_201305);

执行计划

--------------------------------------------------------------------------------------------------------

| Id | Operation | Name | Rows | Bytes | Cost (%cpu)| Time | Pstart| Pstop |

--------------------------------------------------------------------------------------------------------

| 0 | SELECT STATEMENT | | 1 | 8 | 8 (0)| 00:00:01 | | |

| 1 | SORT AGGREGATE | | 1 | 8 | | | | |

| 2 | PARTITION RANGE SINGLE| | 8716 | 69728 | 8 (0)| 00:00:01 | 5 | 5 |

| 3 | INDEX FAST FULL SCAN | IDX_PART_NBR | 8716 | 69728 | 8 (0)| 00:00:01 | 5 | 5 |

--------------------------------------------------------------------------------------------------------

统计信息

----------------------------------------------------------

0 recursive calls

0 db block gets

29 consistent gets

select sum(nbr) max_nbr

from range_part_tab

where deal_date >= TO_DATE('2013-05-01','YYYY-MM-DD');

执行计划

----------------------------------------------------------------------------------------------------------

| Id | Operation | Name | Rows | Bytes | Cost (%cpu)| Time | Pstart| Pstop |

----------------------------------------------------------------------------------------------------------

| 0 | SELECT STATEMENT | | 1 | 17 | 170 (0)| 00:00:03 | | |

| 1 | SORT AGGREGATE | | 1 | 17 | | | | |

| 2 | PARTITION RANGE SINGLE| | 22 | 374 | 170 (0)| 00:00:03 | 5 | 5 |

| 3 | TABLE ACCESS FULL | RANGE_PART_TAB | 22 | 374 | 170 (0)| 00:00:03 | 5 | 5 |

----------------------------------------------------------------------------------------------------------

统计信息

----------------------------------------------------------

0 recursive calls

0 db block gets

568 consistent gets



select distinct(nbr) from range_part_tab partition(p_201305);

执行计划

--------------------------------------------------------------------------------------------------------

| Id | Operation | Name | Rows | Bytes | Cost (%cpu)| Time | Pstart| Pstop |

--------------------------------------------------------------------------------------------------------

| 0 | SELECT STATEMENT | | 8660 | 69280 | 9 (12)| 00:00:01 | | |

| 1 | HASH UNIQUE | | 8660 | 69280 | 9 (12)| 00:00:01 | | |

| 2 | PARTITION RANGE SINGLE| | 8716 | 69728 | 8 (0)| 00:00:01 | 5 | 5 |

| 3 | INDEX FAST FULL SCAN | IDX_PART_NBR | 8716 | 69728 | 8 (0)| 00:00:01 | 5 | 5 |

--------------------------------------------------------------------------------------------------------

统计信息

----------------------------------------------------------

0 recursive calls

0 db block gets

29 consistent gets

0 physical reads

0 redo size

152890 bytes sent via sql*Net to client

6741 bytes received via sql*Net from client

577 sql*Net roundtrips to/from client

0 sorts (memory)

0 sorts (disk)

8635 rows processed

select distinct(nbr)

from range_part_tab

where deal_date >= TO_DATE('2013-05-01','YYYY-MM-DD');

执行计划

----------------------------------------------------------------------------------------------------------

| Id | Operation | Name | Rows | Bytes | Cost (%cpu)| Time | Pstart| Pstop |

----------------------------------------------------------------------------------------------------------

| 0 | SELECT STATEMENT | | 22 | 374 | 171 (1)| 00:00:03 | | |

| 1 | HASH UNIQUE | | 22 | 374 | 171 (1)| 00:00:03 | | |

| 2 | PARTITION RANGE SINGLE| | 22 | 374 | 170 (0)| 00:00:03 | 5 | 5 |

| 3 | TABLE ACCESS FULL | RANGE_PART_TAB | 22 | 374 | 170 (0)| 00:00:03 | 5 | 5 |

----------------------------------------------------------------------------------------------------------

统计信息

----------------------------------------------------------

0 recursive calls

0 db block gets

568 consistent gets

0 physical reads

0 redo size

152886 bytes sent via sql*Net to client

6741 bytes received via sql*Net from client

577 sql*Net roundtrips to/from client

0 sorts (memory)

0 sorts (disk)

8635 rows processed





select count(*)

from range_part_tab

where deal_date >= TO_DATE('2013-05-01 00:00:00','YYYY-MM-DD hh24:mi:ss')

and deal_date <= TO_DATE('2013-06-01 00:00:00','YYYY-MM-DD hh24:mi:ss');

COUNT(*)

----------

8635

执行计划

------------------------------------------------------------------------------------------------------------

| Id | Operation | Name | Rows | Bytes | Cost (%cpu)| Time | Pstart| Pstop |

------------------------------------------------------------------------------------------------------------

| 0 | SELECT STATEMENT | | 1 | 9 | 340 (1)| 00:00:05 | | |

| 1 | SORT AGGREGATE | | 1 | 9 | | | | |

| 2 | PARTITION RANGE ITERATOR| | 497 | 4473 | 340 (1)| 00:00:05 | 5 | 6 |

|* 3 | TABLE ACCESS FULL | RANGE_PART_TAB | 497 | 4473 | 340 (1)| 00:00:05 | 5 | 6 |

------------------------------------------------------------------------------------------------------------

统计信息

----------------------------------------------------------

0 recursive calls

0 db block gets

1136 consistent gets

select count(*)

from range_part_tab

where deal_date >= TO_DATE('2013-05-01 00:00:00','YYYY-MM-DD hh24:mi:ss')

and deal_date < TO_DATE('2013-06-01 00:00:00','YYYY-MM-DD hh24:mi:ss');

COUNT(*)

----------

8635

执行计划

----------------------------------------------------------------------------------------------------------

| Id | Operation | Name | Rows | Bytes | Cost (%cpu)| Time | Pstart| Pstop |

----------------------------------------------------------------------------------------------------------

| 0 | SELECT STATEMENT | | 1 | 9 | 170 (0)| 00:00:03 | | |

| 1 | SORT AGGREGATE | | 1 | 9 | | | | |

| 2 | PARTITION RANGE SINGLE| | 22 | 198 | 170 (0)| 00:00:03 | 5 | 5 |

| 3 | TABLE ACCESS FULL | RANGE_PART_TAB | 22 | 198 | 170 (0)| 00:00:03 | 5 | 5 |

----------------------------------------------------------------------------------------------------------

统计信息

----------------------------------------------------------

0 recursive calls

0 db block gets

568 consistent gets

原文链接:https://www.f2er.com/javaschema/285533.html

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