SQL_ID 4g70n3k9bqc5v, child number 0
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MERGE INTO YJBZH_GRXDFHZMXJL GRXDFHZMXJL USING ( SELECT A.AGMT_ID AS
AGMT_ID, B.CUST_NAME AS CUST_NAME FROM DWF.F_AGT_CADB_BOOK_H A,
DWF.F_AGT_SAVB_BASICINFO_H B WHERE A.START_DT <= TO_DATE(:B1
,'yyyy-mm-dd') AND A.END_DT > TO_DATE(:B1 ,'yyyy-mm-dd') AND B.START_DT
<= TO_DATE(:B1 ,'yyyy-mm-dd') AND B.END_DT > TO_DATE(:B1 ,'yyyy-mm-dd')
AND A.MASTER_CARD_NO = B.AGMT_ID ) SAVB_BASICINFO ON (
RTRIM(GRXDFHZMXJL.DFZH) = SAVB_BASICINFO.AGMT_ID AND CJRQ =
TO_CHAR(TO_DATE(:B1 , 'YYYY-MM-DD'),'yyyymmdd') ) WHEN MATCHED THEN
UPDATE SET GRXDFHZMXJL.DFHM = SAVB_BASICINFO.CUST_NAME
Plan hash value: 2923259190
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| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
---------------------------------------------------------------------------------------------------------
| 0 | MERGE STATEMENT | | | | 44331 (100)| |
| 1 | MERGE | YJBZH_GRXDFHZMXJL | | | | |
| 2 | VIEW | | | | | |
| 3 | NESTED LOOPS | | 1 | 1862 | 44331 (1)| 00:08:52 |
| 4 | NESTED LOOPS | | 15 | 1862 | 44331 (1)| 00:08:52 |
| 5 | MERGE JOIN CARTESIAN | | 1 | 1808 | 44313 (1)| 00:08:52 |
|* 6 | TABLE ACCESS FULL | YJBZH_GRXDFHZMXJL | 1 | 1762 | 26057 (1)| 00:05:13 |
| 7 | BUFFER SORT | | 2120K| 93M| 18256 (2)| 00:03:40 |
|* 8 | TABLE ACCESS FULL | F_AGT_SAVB_BASICINFO_H | 2120K| 93M| 18256 (2)| 00:03:40 |
|* 9 | INDEX RANGE SCAN | F_AGT_CADB_BOOK_H_IDX2 | 15 | | 2 (0)| 00:00:01 |
|* 10 | TABLE ACCESS BY INDEX ROWID| F_AGT_CADB_BOOK_H | 1 | 54 | 18 (0)| 00:00:01 |
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Predicate Information (identified by operation id):
---------------------------------------------------
6 - filter("CJRQ"=TO_CHAR(TO_DATE(:B1,'YYYY-MM-DD'),'yyyymmdd'))
8 - filter(("B"."START_DT"<=TO_DATE(:B1,'yyyy-mm-dd') AND
"B"."END_DT">TO_DATE(:B1,'yyyy-mm-dd')))
9 - access("A"."AGMT_ID"=RTRIM("GRXDFHZMXJL"."DFZH") AND
"A"."END_DT">TO_DATE(:B1,'yyyy-mm-dd') AND "A"."END_DT" IS NOT NULL)
10 - filter(("A"."MASTER_CARD_NO" IS NOT NULL AND "A"."START_DT"<=TO_DATE(:B1,'yyyy-mm-dd')
AND "A"."MASTER_CARD_NO"="B"."AGMT_ID"))
select count(*) from YJBZH_GRXDFHZMXJL
--0
后来发现多个merge在一个会话里,添加日志后表数据有20W+
select count(*) from dwf.F_AGT_SAVB_BASICINFO_H B where (("B"."START_DT"<=TO_DATE(20131231,'yyyy-mm-dd') AND
"B"."END_DT">TO_DATE(20131231,'yyyy-mm-dd')))
---返回了1071795条记录
那此时ID=5 就傻逼了,实际需要至少返回1071795 然后作为驱动集去驱动ID=9 那么F_AGT_CADB_BOOK_H_IDX2 需要扫描1071795次,此时SQL肯定跑不出来
这时候关联顺序变成了YJBZH_GRXDFHZMXJL和F_AGT_SAVB_BASICINFO_H进行笛卡尔积,产生的结果集在和F_AGT_CADB_BOOK_H进行关联,但是看SQL并不是这样
正确的关联顺序是F_AGT_CADB_BOOK_H和F_AGT_SAVB_BASICINFO_H关联产生的结果集在和YJBZH_GRXDFHZMXJL关联。
添加hints:
ORDERED提示强制Oracle按照From子句中表出现的顺序进行表连接。
通过ORDERED提示，可以避免CBO SQL解析过程中的表连接评估，从而避免Oracle产生错误的执行计划，或者强制Oracle按照我们指定的方式执行。在很多时候，当我们清楚地了解数据结构和数据分布之后，就可以通过ORDERED提示来提高SQL性能。
SQL_ID cw628tpmjcbjv, child number 0
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MERGE /*+ordered*/ INTO YJBZH_GRXDFHZMXJL GRXDFHZMXJL USING ( SELECT
A.AGMT_ID AS AGMT_ID, B.CUST_NAME AS CUST_NAME FROM
DWF.F_AGT_CADB_BOOK_H A, DWF.F_AGT_SAVB_BASICINFO_H B WHERE A.START_DT
<= TO_DATE(:B1 ,'yyyy-mm-dd') AND A.END_DT > TO_DATE(:B1 ,'yyyy-mm-dd')
AND B.START_DT <= TO_DATE(:B1 ,'yyyy-mm-dd') AND B.END_DT > TO_DATE(:B1
,'yyyy-mm-dd') AND A.MASTER_CARD_NO = B.AGMT_ID ) SAVB_BASICINFO ON (
RTRIM(GRXDFHZMXJL.DFZH) = SAVB_BASICINFO.AGMT_ID AND CJRQ =
TO_CHAR(TO_DATE(:B1 , 'YYYY-MM-DD'),'yyyymmdd') ) WHEN MATCHED THEN
UPDATE SET GRXDFHZMXJL.DFHM = SAVB_BASICINFO.CUST_NAME
Plan hash value: 2400855618
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| Id | Operation | Name | Rows | Bytes |TempSpc| Cost (%CPU)| Time |
--------------------------------------------------------------------------------------------------------
| 0 | MERGE STATEMENT | | | | | 138K(100)| |
| 1 | MERGE | YJBZH_GRXDFHZMXJL | | | | | |
| 2 | VIEW | | | | | | |
|* 3 | HASH JOIN | | 1 | 1862 | | 138K (2)| 00:27:39 |
|* 4 | TABLE ACCESS FULL | YJBZH_GRXDFHZMXJL | 1 | 1762 | | 26057 (1)| 00:05:13 |
|* 5 | HASH JOIN | | 11M| 1074M| 374M| 112K (2)| 00:22:25 |
|* 6 | TABLE ACCESS FULL| F_AGT_CADB_BOOK_H | 5951K| 306M| | 69245 (2)| 00:13:51 |
|* 7 | TABLE ACCESS FULL| F_AGT_SAVB_BASICINFO_H | 2120K| 93M| | 18256 (2)| 00:03:40 |
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Predicate Information (identified by operation id):
---------------------------------------------------
3 - access("A"."AGMT_ID"=RTRIM("GRXDFHZMXJL"."DFZH"))
4 - filter("CJRQ"=TO_CHAR(TO_DATE(:B1,'YYYY-MM-DD'),'yyyymmdd'))
5 - access("A"."MASTER_CARD_NO"="B"."AGMT_ID")
6 - filter(("A"."MASTER_CARD_NO" IS NOT NULL AND "A"."START_DT"<=TO_DATE(:B1,'yyyy-mm-dd')
AND "A"."END_DT">TO_DATE(:B1,'yyyy-mm-dd')))
7 - filter(("B"."START_DT"<=TO_DATE(:B1,'yyyy-mm-dd') AND
"B"."END_DT">TO_DATE(:B1,'yyyy-mm-dd')))