今天下午盖尔又发来一条坑爹的SQL，哎，最近被盖尔给咕噜惨了，老是发一些鸟SQL让我调，最近都帮忙调了N多个SQL了，还好盖尔良心发现了，说这个月末给我重200元的话费
。认识盖尔的人都知道，盖尔发的SQL那绝对是坑爹的，说它是OLTP的SQL不像，因为OLTP的SQL没那么复杂，说它是OLAP的也不像，因为我没看见典型的事实表，维度表的JOIN，那么唯一的解释就是他们DB设计的人是SB。
盖尔的SQL和执行计划如下：
select distinct decode(length(a.category_id),
5,
decode(a.origin_type, 801, 888888, 999999),
a.category_id) category_id,
a.notice_code,
a.treat_status,
lr.real_name as receiver_name,
f.send_code,
f.policy_code,
g.real_name agent_name,
f.organ_id,
f.dept_id,
a.policy_id,
a.change_id,
a.case_id,
a.group_policy_id,
a.fee_id,
a.auth_id,
a.pay_id,
cancel_appoint.appoint_time cancel_appoint_time,
a.insert_time,
a.send_time,
a.end_time,
f.agency_code,
a.REPLY_TIME,
a.REPLY_EMP_ID,
a.FIRST_DUTY,
a.NEED_SEND_PRINT,
11 source
from t_policy_problem a,
t_policy f,
t_agent g,
t_letter_receiver lr,
t_problem_category pc,
t_policy_cancel_appoint cancel_appoint
where f.agent_id = g.agent_id(+)
and a.policy_id = f.policy_id(+)
and lr.main_receiver = 'Y'
and a.category_id = pc.category_id
and a.item_id = lr.item_id
and a.policy_id = cancel_appoint.policy_id(+)
And a.Item_Id = (Select Max(item_id)
From t_Policy_Problem
Where notice_code = a.notice_code)
and a.policy_id is not null
and a.notice_code is not null
and a.change_id is null
and a.case_id is null
and a.group_policy_id is null
and a.origin_type not in (801, 802)
and a.pay_id is null
and a.category_id not in (130103, 130104, 130102, 140102, 140101)
and f.policy_type = '1'
and (a.fee_id is null or (a.fee_id is not null and a.origin_type = 701))
and exists((select 1
from t_dept
where f.dept_id = dept_id
start with dept_id = '1020200028'
connect by parent_id = prior dept_id))
and exists (select 1
from T_COMPANY_ORGAN
where f.organ_id = organ_id
start with organ_id = '10202'
connect by parent_id = prior organ_id)
and pc.NEED_PRITN = 'Y';
SQL> select * from table(dbms_xplan.display);
PLAN_TABLE_OUTPUT
-------------------------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)|
-------------------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 236 | 741 (1)|
| 1 | SORT UNIQUE | | 1 | 236 | 681 (0)|
|* 2 | FILTER | | | | |
| 3 | NESTED LOOPS | | 1 | 236 | 666 (1)|
| 4 | NESTED LOOPS OUTER | | 1 | 219 | 665 (1)|
| 5 | NESTED LOOPS | | 1 | 203 | 664 (1)|
| 6 | NESTED LOOPS OUTER | | 1 | 196 | 663 (1)|
| 7 | NESTED LOOPS | | 1 | 182 | 662 (1)|
|* 8 | TABLE ACCESS FULL | T_POLICY_PROBLEM | 1 | 107 | 660 (0)|
|* 9 | TABLE ACCESS BY INDEX ROWID| T_POLICY | 1 | 75 | 2 (50)|
|* 10 | INDEX UNIQUE SCAN | PK_T_POLICY | 1 | | 1 (0)|
| 11 | TABLE ACCESS BY INDEX ROWID | T_POLICY_CANCEL_APPOINT | 1 | 14 | 2 (50)|
|* 12 | INDEX UNIQUE SCAN | UK1_POLICY_CANCEL_APPOINT | 1 | | |
|* 13 | TABLE ACCESS BY INDEX ROWID | T_PROBLEM_CATEGORY | 1 | 7 | 2 (50)|
|* 14 | INDEX UNIQUE SCAN | PK_T_PROBLEM_CATEGORY | 1 | | |
| 15 | TABLE ACCESS BY INDEX ROWID | T_AGENT | 1 | 16 | 2 (50)|
|* 16 | INDEX UNIQUE SCAN | PK_T_AGENT | 1 | | |
|* 17 | INDEX RANGE SCAN | T_LETTER_RECEIVER_IDX_001 | 1 | 17 | 2 (0)|
| 18 | SORT AGGREGATE | | 1 | 21 | |
| 19 | TABLE ACCESS BY INDEX ROWID | T_POLICY_PROBLEM | 1 | 21 | 2 (50)|
|* 20 | INDEX RANGE SCAN | IDX_POLICY_PROBLEM__N_CODE | 1 | | 3 (0)|
|* 21 | FILTER | | | | |
|* 22 | CONNECT BY WITH FILTERING | | | | |
| 23 | NESTED LOOPS | | | | |
|* 24 | INDEX UNIQUE SCAN | PK_T_DEPT | 1 | 17 | 1 (0)|
| 25 | TABLE ACCESS BY USER ROWID | T_DEPT | | | |
| 26 | HASH JOIN | | | | |
| 27 | CONNECT BY PUMP | | | | |
| 28 | TABLE ACCESS FULL | T_DEPT | 30601 | 896K| 56 (0)|
|* 29 | FILTER | | | | |
|* 30 | CONNECT BY WITH FILTERING | | | | |
| 31 | NESTED LOOPS | | | | |
|* 32 | INDEX UNIQUE SCAN | PK_T_COMPANY_ORGAN | 1 | 6 | |
| 33 | TABLE ACCESS BY USER ROWID | T_COMPANY_ORGAN | | | |
| 34 | NESTED LOOPS | | | | |
| 35 | BUFFER SORT | | 7 | 70 | |
| 36 | CONNECT BY PUMP | | | | |
|* 37 | INDEX RANGE SCAN | T_COMPANY_ORGAN_IDX_002 | 7 | 70 | 1 (0)|
-------------------------------------------------------------------------------------------------------
2 - filter("SYS_ALIAS_1"."ITEM_ID"= (SELECT /*+ */ MAX("T_POLICY_PROBLEM"."ITEM_ID") FROM
"T_POLICY_PROBLEM" "T_POLICY_PROBLEM" WHERE "T_POLICY_PROBLEM"."NOTICE_CODE"=:B1) AND EXISTS (SELECT
/*+ */ 0 FROM "T_DEPT" "T_DEPT" AND ("T_DEPT"."DEPT_ID"=:B2)) AND EXISTS (SELECT /*+ */ 0 FROM
"T_COMPANY_ORGAN" "T_COMPANY_ORGAN" WHERE "T_COMPANY_ORGAN"."PARENT_ID"=NULL AND
("T_COMPANY_ORGAN"."ORGAN_ID"=:B3)))
8 - filter("SYS_ALIAS_1"."POLICY_ID" IS NOT NULL AND "SYS_ALIAS_1"."NOTICE_CODE" IS NOT NULL AND
"SYS_ALIAS_1"."CHANGE_ID" IS NULL AND "SYS_ALIAS_1"."CASE_ID" IS NULL AND
"SYS_ALIAS_1"."GROUP_POLICY_ID" IS NULL AND TO_NUMBER("SYS_ALIAS_1"."ORIGIN_TYPE")<>801 AND
TO_NUMBER("SYS_ALIAS_1"."ORIGIN_TYPE")<>802 AND "SYS_ALIAS_1"."PAY_ID" IS NULL AND
"SYS_ALIAS_1"."CATEGORY_ID"<>130103 AND "SYS_ALIAS_1"."CATEGORY_ID"<>130104 AND
"SYS_ALIAS_1"."CATEGORY_ID"<>130102 AND "SYS_ALIAS_1"."CATEGORY_ID"<>140102 AND
"SYS_ALIAS_1"."CATEGORY_ID"<>140101 AND ("SYS_ALIAS_1"."FEE_ID" IS NULL OR "SYS_ALIAS_1"."FEE_ID" IS
NOT NULL AND TO_NUMBER("SYS_ALIAS_1"."ORIGIN_TYPE")=701))
9 - filter(TO_NUMBER("SYS_ALIAS_3"."POLICY_TYPE")=1)
10 - access("SYS_ALIAS_1"."POLICY_ID"="SYS_ALIAS_3"."POLICY_ID")
12 - access("SYS_ALIAS_1"."POLICY_ID"="CANCEL_APPOINT"."POLICY_ID"(+))
13 - filter("PC"."NEED_PRITN"='Y')
14 - access("SYS_ALIAS_1"."CATEGORY_ID"="PC"."CATEGORY_ID")
filter("PC"."CATEGORY_ID"<>130103 AND "PC"."CATEGORY_ID"<>130104 AND "PC"."CATEGORY_ID"<>130102
AND "PC"."CATEGORY_ID"<>140102 AND "PC"."CATEGORY_ID"<>140101)
16 - access("SYS_ALIAS_3"."AGENT_ID"="G"."AGENT_ID"(+))
17 - access("LR"."MAIN_RECEIVER"='Y' AND "SYS_ALIAS_1"."ITEM_ID"="LR"."ITEM_ID")
20 - access("T_POLICY_PROBLEM"."NOTICE_CODE"=:B1)
21 - filter("T_DEPT"."DEPT_ID"=:B1)
22 - filter("T_DEPT"."DEPT_ID"='1020200028')
24 - access("T_DEPT"."DEPT_ID"='1020200028')
29 - filter("T_COMPANY_ORGAN"."ORGAN_ID"=:B1)
30 - filter("T_COMPANY_ORGAN"."ORGAN_ID"='10202')
32 - access("T_COMPANY_ORGAN"."ORGAN_ID"='10202')
37 - access("T_COMPANY_ORGAN"."PARENT_ID"=NULL)
77 rows selected.
这个SQL里面又有 (TO_NUMBER("SYS_ALIAS_3"."POLICY_TYPE")=1) ，写SQL的那人啊 为啥又不加上'' 他们的开发人员水平真的是太那个啥了
盖尔说这个SQL跑不出结果，让他查询等待事件，是 db file sequential read
这个SQL之所以跑不出结果是因为子查询里面有 start with.... connect by ，
子查询外面使用的是exists，CBO里面有个限制：当子查询里面有 start with....connect by ， CBO不会对子查询进行转换，所以这个时候就只能走filter了
但是子查询又要返回很多结果 所以帮盖尔改写了SQL，用in 代替 exists
select distinct decode(length(a.category_id),
5,
decode(a.origin_type, 801, 888888, 999999),
a.category_id) category_id,
a.notice_code,
a.treat_status,
lr.real_name as receiver_name,
f.send_code,
f.policy_code,
g.real_name agent_name,
f.organ_id,
f.dept_id,
a.policy_id,
a.change_id,
a.case_id,
a.group_policy_id,
a.fee_id,
a.auth_id,
a.pay_id,
cancel_appoint.appoint_time cancel_appoint_time,
a.insert_time,
a.send_time,
a.end_time,
f.agency_code,
a.REPLY_TIME,
a.REPLY_EMP_ID,
a.FIRST_DUTY,
a.NEED_SEND_PRINT,
11 source
from t_policy_problem a,
t_policy f,
t_agent g,
t_letter_receiver lr,
t_problem_category pc,
t_policy_cancel_appoint cancel_appoint
where f.agent_id = g.agent_id(+)
and a.policy_id = f.policy_id(+)
and lr.main_receiver = 'Y'
and a.category_id = pc.category_id
and a.item_id = lr.item_id
and a.policy_id = cancel_appoint.policy_id(+)
And a.Item_Id = (Select Max(item_id)
From t_Policy_Problem
Where notice_code = a.notice_code)
and a.policy_id is not null
and a.notice_code is not null
and a.change_id is null
and a.case_id is null
and a.group_policy_id is null
and a.origin_type not in (801, 802)
and a.pay_id is null
and a.category_id not in (130103, 130104, 130102, 140102, 140101)
and f.policy_type = '1'
and (a.fee_id is null or (a.fee_id is not null and a.origin_type = 701))
and f.dept_id in (select dept_id
from t_dept
start with dept_id = '1020200028'
connect by parent_id = prior dept_id))
and f.organ_id in (select organ_id
from T_COMPANY_ORGAN
start with organ_id = '10202'
connect by parent_id = prior organ_id)
and pc.NEED_PRITN = 'Y';
----------------------------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)|
----------------------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 259 | 742 (1)|
| 1 | SORT UNIQUE | | 1 | 259 | 740 (0)|
|* 2 | FILTER | | | | |
|* 3 | HASH JOIN | | 1 | 259 | 725 (1)|
| 4 | NESTED LOOPS | | 1 | 253 | 723 (1)|
| 5 | NESTED LOOPS | | 1 | 236 | 722 (1)|
| 6 | NESTED LOOPS OUTER | | 1 | 229 | 721 (1)|
| 7 | NESTED LOOPS OUTER | | 1 | 215 | 720 (1)|
|* 8 | HASH JOIN | | 1 | 199 | 719 (1)|
| 9 | NESTED LOOPS | | 1 | 182 | 662 (1)|
|* 10 | TABLE ACCESS FULL | T_POLICY_PROBLEM | 1 | 107 | 660 (0)|
|* 11 | TABLE ACCESS BY INDEX ROWID | T_POLICY | 1 | 75 | 2 (50)|
|* 12 | INDEX UNIQUE SCAN | PK_T_POLICY | 1 | | 1 (0)|
| 13 | VIEW | VW_NSO_1 | 30601 | 508K| |
|* 14 | CONNECT BY WITH FILTERING | | | | |
| 15 | NESTED LOOPS | | | | |
|* 16 | INDEX UNIQUE SCAN | PK_T_DEPT | 1 | 17 | 1 (0)|
| 17 | TABLE ACCESS BY USER ROWID| T_DEPT | | | |
| 18 | HASH JOIN | | | | |
| 19 | CONNECT BY PUMP | | | | |
| 20 | TABLE ACCESS FULL | T_DEPT | 30601 | 896K| 56 (0)|
| 21 | TABLE ACCESS BY INDEX ROWID | T_AGENT | 1 | 16 | 2 (50)|
|* 22 | INDEX UNIQUE SCAN | PK_T_AGENT | 1 | | |
| 23 | TABLE ACCESS BY INDEX ROWID | T_POLICY_CANCEL_APPOINT | 1 | 14 | 2 (50)|
|* 24 | INDEX UNIQUE SCAN | UK1_POLICY_CANCEL_APPOINT | 1 | | |
|* 25 | TABLE ACCESS BY INDEX ROWID | T_PROBLEM_CATEGORY | 1 | 7 | 2 (50)|
|* 26 | INDEX UNIQUE SCAN | PK_T_PROBLEM_CATEGORY | 1 | | |
|* 27 | INDEX RANGE SCAN | T_LETTER_RECEIVER_IDX_001 | 1 | 17 | 2 (0)|
| 28 | VIEW | VW_NSO_2 | 7 | 42 | |
|* 29 | CONNECT BY WITH FILTERING | | | | |
| 30 | NESTED LOOPS | | | | |
|* 31 | INDEX UNIQUE SCAN | PK_T_COMPANY_ORGAN | 1 | 6 | |
| 32 | TABLE ACCESS BY USER ROWID | T_COMPANY_ORGAN | | | |
| 33 | NESTED LOOPS | | | | |
| 34 | BUFFER SORT | | 7 | 70 | |
| 35 | CONNECT BY PUMP | | | | |
|* 36 | INDEX RANGE SCAN | T_COMPANY_ORGAN_IDX_002 | 7 | 70 | 1 (0)|
| 37 | SORT AGGREGATE | | 1 | 21 | |
| 38 | TABLE ACCESS BY INDEX ROWID | T_POLICY_PROBLEM | 1 | 21 | 2 (50)|
|* 39 | INDEX RANGE SCAN | IDX_POLICY_PROBLEM__N_CODE | 1 | | 3 (0)|
----------------------------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
2 - filter("SYS_ALIAS_1"."ITEM_ID"= (SELECT /*+ */ MAX("T_POLICY_PROBLEM"."ITEM_ID") FROM
"T_POLICY_PROBLEM" "T_POLICY_PROBLEM" WHERE "T_POLICY_PROBLEM"."NOTICE_CODE"=:B1))
3 - access("F"."ORGAN_ID"="VW_NSO_2"."$nso_col_1")
8 - access("F"."DEPT_ID"="VW_NSO_1"."$nso_col_1")
10 - filter("SYS_ALIAS_1"."POLICY_ID" IS NOT NULL AND "SYS_ALIAS_1"."NOTICE_CODE" IS NOT NULL AND
"SYS_ALIAS_1"."CHANGE_ID" IS NULL AND "SYS_ALIAS_1"."CASE_ID" IS NULL AND "SYS_ALIAS_1"."GROUP_POLICY_ID"
IS NULL AND TO_NUMBER("SYS_ALIAS_1"."ORIGIN_TYPE")<>801 AND TO_NUMBER("SYS_ALIAS_1"."ORIGIN_TYPE")<>802
AND "SYS_ALIAS_1"."PAY_ID" IS NULL AND "SYS_ALIAS_1"."CATEGORY_ID"<>130103 AND
"SYS_ALIAS_1"."CATEGORY_ID"<>130104 AND "SYS_ALIAS_1"."CATEGORY_ID"<>130102 AND
"SYS_ALIAS_1"."CATEGORY_ID"<>140102 AND "SYS_ALIAS_1"."CATEGORY_ID"<>140101 AND ("SYS_ALIAS_1"."FEE_ID"
IS NULL OR "SYS_ALIAS_1"."FEE_ID" IS NOT NULL AND TO_NUMBER("SYS_ALIAS_1"."ORIGIN_TYPE")=701))
11 - filter("F"."POLICY_TYPE"='1')
12 - access("SYS_ALIAS_1"."POLICY_ID"="F"."POLICY_ID")
14 - filter("T_DEPT"."DEPT_ID"='1020200028')
16 - access("T_DEPT"."DEPT_ID"='1020200028')
22 - access("F"."AGENT_ID"="G"."AGENT_ID"(+))
24 - access("SYS_ALIAS_1"."POLICY_ID"="CANCEL_APPOINT"."POLICY_ID"(+))
25 - filter("PC"."NEED_PRITN"='Y')
26 - access("SYS_ALIAS_1"."CATEGORY_ID"="PC"."CATEGORY_ID")
filter("PC"."CATEGORY_ID"<>130103 AND "PC"."CATEGORY_ID"<>130104 AND "PC"."CATEGORY_ID"<>130102
AND "PC"."CATEGORY_ID"<>140102 AND "PC"."CATEGORY_ID"<>140101)
27 - access("LR"."MAIN_RECEIVER"='Y' AND "SYS_ALIAS_1"."ITEM_ID"="LR"."ITEM_ID")
29 - filter("T_COMPANY_ORGAN"."ORGAN_ID"='10202')
31 - access("T_COMPANY_ORGAN"."ORGAN_ID"='10202')
36 - access("T_COMPANY_ORGAN"."PARENT_ID"=NULL)
39 - access("T_POLICY_PROBLEM"."NOTICE_CODE"=:B1)
75 rows selected.
SQL 改写之后，35秒就能出结果了，以前是不出结果啊！恩，这个SQL优化就到此为止吧。
我还想提的就是，他的这个SQL里面的过滤条件，
and a.policy_id is not null
and a.notice_code is not null
and a.change_id is null
and a.case_id is null
and a.group_policy_id is null
and a.origin_type not in (801, 802)
and a.pay_id is null
and a.category_id not in (130103, 130104, 130102, 140102, 140101)
is null, is not null , not in ...... 这都是什么需求啊，这个系统设计人员确实“牛逼”
这个案例恰好和 http://blog.csdn.net/robinson1988/article/details/7002545 这个案例完全相反，所以，当你遇到子查询里面有树形查询，子查询选择使用in/exists需要特别留意