来OB这么久还没有接触啥金融的SQL，只能发点其他行业的数据库SQL优化案例。😂
今天拿到手的这个案例SQL 传统行业的，很奇葩的SQL，表设计三范式都没弄好。
什么医疗，交通，能源这些传统行业的业务设计，SQL语句最奇葩了，也挺好玩的，有挑战性。
慢SQL：
SELECT LI.STATUS, FI.SOFL_SEQ_NR ,PI.CLAZZ,PI.HV_TYPE
FROM LNF LI, PNF PI, FNF FI
WHERE 1=1
AND LI.ALN_CD = DECODE(FI.ALN_CD, 'OQ', 'CZ', FI.ALN_CD)
and li.dep_arp_cd = fi.act_dep_cd
and li.flt_nr = DECODE(fi.aln_cd,'OQ',substr(( select cz_flt_nr from OQ_FLT_INFO oq where substr(oq.oq_flt_nr,3,4)= fi.flt_nr) ,3,4), fi.flt_nr)
and li.FLT_DT=FI.FLT_DT
AND LI.FK_PSGR_ID = PI.PSGR_ID
AND (PI.HV_TYPE IS NOT NULL OR PI.CLAZZ IN ('F', 'F1', 'J', 'C', 'D', 'I', 'O'))
and FI.FLT_DT=date'2024-04-01'
and FI.SCH_DEP_CD='CAN'
ORDER BY FI.SOFL_SEQ_NR ;执行时间：
执行计划（看不看得懂随缘、反正我没看）：
1 #NSET2: [2903, 556029, 632]
2 #PIPE2: [2903, 556029, 632]
3 #PIPE2: [2901, 556029, 632]
4 #PRJT2: [2899, 556029, 632]; exp_num(4), is_atom(FALSE)
5 #SORT3: [2899, 556029, 632]; key_num(1), is_distinct(FALSE), top_flag(0), is_adaptive(0)
6 #UNION FOR OR2: [2788, 556029, 632]; key_num(0), outer_join(-)
7 #SLCT2: [1334, 278014, 632]; LI.FLT_NR = exp_simple_case
8 #HASH2 INNER JOIN: [1334, 278014, 632]; KEY_NUM(2); KEY(FI.ACT_DEP_CD=LI.DEP_ARP_CD AND exp_simple_case=LI.ALN_CD) KEY_NULL_EQU(0, 0)
9 #BLKUP2: [1, 385, 247]; IDX_FLIGHT_INFO02(FI)
10 #SSEK2: [1, 385, 247]; scan_type(ASC), IDX_FLIGHT_INFO02(FNF as FI), scan_range[(exp_cast(2024-04-01),'CAN',min),(exp_cast(2024-04-01),'CAN',max))
11 #SLCT2: [1324, 37479, 385]; NOT(PI.HV_TYPE IS NULL)
12 #HASH2 INNER JOIN: [1324, 37479, 385]; RKEY_UNIQUE KEY_NUM(1); KEY(LI.FK_PSGR_ID=PI.PSGR_ID) KEY_NULL_EQU(0)
13 #SLCT2: [1324, 37479, 385]; NOT(PI.HV_TYPE IS NULL)
14 #NEST LOOP INDEX JOIN2: [1324, 37479, 385]
15 #ACTRL: [1324, 37479, 385];
16 #BLKUP2: [1049, 37479, 247]; INDEX_LU_INTO_TAG_0416(LI)
17 #SLCT2: [1049, 37479, 247]; LI.FLT_DT = var3
18 #SSCN: [1049, 37479, 247]; INDEX_LU_INTO_TAG_0416(LNF as LI); btr_scan(1)
19 #BLKUP2: [244, 1, 30]; INDEX33555482(PI)
20 #SSEK2: [244, 1, 30]; scan_type(ASC), INDEX33555482(PNF as PI), scan_range[LI.FK_PSGR_ID,LI.FK_PSGR_ID]
21 #CSCN2: [475, 3573399, 138]; INDEX33555481(PNF as PI); btr_scan(1)
22 #SLCT2: [1334, 278014, 632]; LI.FLT_NR = exp_simple_case
23 #HASH2 INNER JOIN: [1334, 278014, 632]; KEY_NUM(2); KEY(FI.ACT_DEP_CD=LI.DEP_ARP_CD AND exp_simple_case=LI.ALN_CD) KEY_NULL_EQU(0, 0)
24 #BLKUP2: [1, 385, 247]; IDX_FLIGHT_INFO02(FI)
25 #SSEK2: [1, 385, 247]; scan_type(ASC), IDX_FLIGHT_INFO02(FNF as FI), scan_range[(exp_cast(2024-04-01),'CAN',min),(exp_cast(2024-04-01),'CAN',max))
26 #SLCT2: [1324, 37479, 385]; (exp11 AND PI.CLAZZ IN LIST)
27 #HASH2 INNER JOIN: [1324, 37479, 385]; RKEY_UNIQUE KEY_NUM(1); KEY(LI.FK_PSGR_ID=PI.PSGR_ID) KEY_NULL_EQU(0)
28 #SLCT2: [1324, 37479, 385]; (exp11 AND PI.CLAZZ IN LIST)
29 #NEST LOOP INDEX JOIN2: [1324, 37479, 385]
30 #ACTRL: [1324, 37479, 385];
31 #BLKUP2: [1049, 37479, 247]; INDEX_LU_INTO_TAG_0416(LI)
32 #SLCT2: [1049, 37479, 247]; LI.FLT_DT = var4
33 #SSCN: [1049, 37479, 247]; INDEX_LU_INTO_TAG_0416(LNF as LI); btr_scan(1)
34 #BLKUP2: [244, 1, 30]; INDEX33555482(PI)
35 #SSEK2: [244, 1, 30]; scan_type(ASC), INDEX33555482(PNF as PI), scan_range[LI.FK_PSGR_ID,LI.FK_PSGR_ID]
36 #CSCN2: [475, 3573399, 138]; INDEX33555481(PNF as PI); btr_scan(1)
37 #SPL2: [1, 279, 343]; key_num(2), spool_num(1), is_atom(FALSE), has_var(0), sites(-)
38 #PRJT2: [1, 279, 343]; exp_num(2), is_atom(FALSE)
39 #HASH2 INNER JOIN: [1, 279, 343]; KEY_NUM(1); KEY(exp11=FI.FLT_NR) KEY_NULL_EQU(0)
40 #CSCN2: [1, 279, 96]; INDEX33555478(OQ_FLT_INFO as OQ); btr_scan(1)
41 #BLKUP2: [1, 385, 247]; IDX_FLIGHT_INFO02(FI)
42 #SSEK2: [1, 385, 247]; scan_type(ASC), IDX_FLIGHT_INFO02(FNF as FI), scan_range[(exp_cast(2024-04-01),'CAN',min),(exp_cast(2024-04-01),'CAN',max))
43 #SPL2: [1, 279, 343]; key_num(2), spool_num(0), is_atom(FALSE), has_var(0), sites(-)
44 #PRJT2: [1, 279, 343]; exp_num(2), is_atom(FALSE)
45 #HASH2 INNER JOIN: [1, 279, 343]; KEY_NUM(1); KEY(exp11=FI.FLT_NR) KEY_NULL_EQU(0)
46 #CSCN2: [1, 279, 96]; INDEX33555478(OQ_FLT_INFO as OQ); btr_scan(1)
47 #BLKUP2: [1, 385, 247]; IDX_FLIGHT_INFO02(FI)
48 #SSEK2: [1, 385, 247]; scan_type(ASC), IDX_FLIGHT_INFO02(FNF as FI), scan_range[(exp_cast(2024-04-01),'CAN',min),(exp_cast(2024-04-01),'CAN',max))表数据量：
上面SQL跑28秒，返回8行数据，还是挺慢的。
DM哥们说他已经加个HINT对 or 进行整体优化，但是还要跑12秒，客户不接受，所以找到我来看看。😅
加HINT优化方案：
SELECT /*+ OPTIMIZER_OR_NBEXP(2) */ LI.STATUS, FI.SOFL_SEQ_NR ,PI.CLAZZ,PI.HV_TYPE
FROM LNF LI, PNF PI, FNF FI
WHERE 1=1
AND LI.ALN_CD = DECODE(FI.ALN_CD, 'OQ', 'CZ', FI.ALN_CD)
and li.dep_arp_cd = fi.act_dep_cd
and li.flt_nr = DECODE(fi.aln_cd,'OQ',substr(( select cz_flt_nr from OQ_FLT_INFO oq where substr(oq.oq_flt_nr,3,4)= fi.flt_nr) ,3,4), fi.flt_nr)
and li.FLT_DT=FI.FLT_DT
AND LI.FK_PSGR_ID = PI.PSGR_ID
AND (PI.HV_TYPE IS NOT NULL OR PI.CLAZZ IN ('F', 'F1', 'J', 'C', 'D', 'I', 'O'))
and FI.FLT_DT=date'2024-04-01'
and FI.SCH_DEP_CD='CAN'
ORDER BY FI.SOFL_SEQ_NR ;加HINT后执行计划：
1 #NSET2: [1372, 278014, 608]
2 #PIPE2: [1372, 278014, 608]
3 #PRJT2: [1371, 278014, 608]; exp_num(4), is_atom(FALSE)
4 #SORT3: [1371, 278014, 608]; key_num(1), is_distinct(FALSE), top_flag(0), is_adaptive(0)
5 #SLCT2: [1317, 278014, 608]; LI.FLT_NR = exp_simple_case
6 #HASH2 INNER JOIN: [1317, 278014, 608]; KEY_NUM(2); KEY(FI.ACT_DEP_CD=LI.DEP_ARP_CD AND exp_simple_case=LI.ALN_CD) KEY_NULL_EQU(0, 0)
7 #BLKUP2: [1, 385, 247]; IDX_FLIGHT_INFO02(FI)
8 #SSEK2: [1, 385, 247]; scan_type(ASC), IDX_FLIGHT_INFO02(FNF as FI), scan_range[(exp_cast(2024-04-01),'CAN',min),(exp_cast(2024-04-01),'CAN',max))
9 #SLCT2: [1307, 37479, 361]; (NOT(PI.HV_TYPE IS NULL) OR PI.CLAZZ IN LIST)
10 #HASH2 INNER JOIN: [1307, 37479, 361]; RKEY_UNIQUE KEY_NUM(1); KEY(LI.FK_PSGR_ID=PI.PSGR_ID) KEY_NULL_EQU(0)
11 #SLCT2: [1307, 37479, 361]; (NOT(PI.HV_TYPE IS NULL) OR PI.CLAZZ IN LIST)
12 #NEST LOOP INDEX JOIN2: [1307, 37479, 361]
13 #ACTRL: [1307, 37479, 361];
14 #BLKUP2: [1032, 37479, 235]; INDEX_LU_INTO_TAG_0416(LI)
15 #SLCT2: [1032, 37479, 235]; LI.FLT_DT = var2
16 #SSCN: [1032, 37479, 235]; INDEX_LU_INTO_TAG_0416(LNF as LI); btr_scan(1)
17 #BLKUP2: [244, 1, 30]; INDEX33555482(PI)
18 #SSEK2: [244, 1, 30]; scan_type(ASC), INDEX33555482(PNF as PI), scan_range[LI.FK_PSGR_ID,LI.FK_PSGR_ID]
19 #CSCN2: [467, 3573399, 126]; INDEX33555481(PNF as PI); btr_scan(1)
20 #SPL2: [1, 279, 343]; key_num(2), spool_num(0), is_atom(FALSE), has_var(0), sites(-)
21 #PRJT2: [1, 279, 343]; exp_num(2), is_atom(FALSE)
22 #HASH2 INNER JOIN: [1, 279, 343]; KEY_NUM(1); KEY(exp11=FI.FLT_NR) KEY_NULL_EQU(0)
23 #CSCN2: [1, 279, 96]; INDEX33555478(OQ_FLT_INFO as OQ); btr_scan(1)
24 #BLKUP2: [1, 385, 247]; IDX_FLIGHT_INFO02(FI)
25 #SSEK2: [1, 385, 247]; scan_type(ASC), IDX_FLIGHT_INFO02(FNF as FI), scan_range[(exp_cast(2024-04-01),'CAN',min),(exp_cast(2024-04-01),'CAN',max))HINT 执行时间：
12秒对原来的28秒来说已经提升了很大的空间，但是客户表示不满意：ORACLE能秒出结果，到了达梦以后执行时间多了12倍，接受不了。😅
无解，最后找到哥，看看能不能帮他让这条SQL"秒出结果"。😎
简单看了看，加索引和使用HINT都不好使，只能等价改写了，再创建合适的索引，让这条SQL走上新的索引。
等价改写 + 索引优化方案：
SELECT LI.STATUS,
FI.SOFL_SEQ_NR,
PI.CLAZZ,
PI.HV_TYPE
FROM LNF LI
INNER JOIN (SELECT ACT_DEP_CD,
FLT_DT,
SOFL_SEQ_NR,
DECODE(ALN_CD, 'OQ', 'CZ', ALN_CD) V1,
DECODE(ALN_CD, 'OQ', SUBSTR(
(SELECT CZ_FLT_NR FROM OQ_FLT_INFO OQ WHERE SUBSTR(OQ.OQ_FLT_NR, 3, 4) = FLT_NR), 3,
4), FLT_NR) V2
FROM FNF
WHERE FLT_DT = DATE'2024-04-01'
AND SCH_DEP_CD = 'CAN'
AND ROWNUM > 0) FI
ON LI.DEP_ARP_CD = FI.ACT_DEP_CD AND LI.FLT_DT = FI.FLT_DT AND LI.ALN_CD = FI.V1 AND
LI.FLT_NR = FI.V2
INNER JOIN (WITH PI AS (SELECT PSGR_ID, HV_TYPE, CLAZZ
FROM PNF)
SELECT DISTINCT PSGR_ID, HV_TYPE, CLAZZ
FROM (SELECT PSGR_ID, HV_TYPE, CLAZZ
FROM PI
WHERE (PI.HV_TYPE IS NOT NULL)
UNION ALL
SELECT PSGR_ID, HV_TYPE, CLAZZ
FROM PI
WHERE PI.CLAZZ IN ('F', 'F1', 'J', 'C', 'D', 'I', 'O'))) PI ON LI.FK_PSGR_ID = PI.PSGR_ID
ORDER BY FI.SOFL_SEQ_NR;
-- 加索引：
create index idx_pi_1_2 on PNF( PSGR_ID,CLAZZ,HV_TYPE );
create index idx_fi_1_2 on FNF ( act_dep_cd,FLT_DT );
CREATE index idx_1_2_3_FI on FNF(FLT_DT,SCH_DEP_CD,act_dep_cd,SOFL_SEQ_NR);
CREATE index idx_1_2_3_li on LNF(ALN_CD,dep_arp_cd,flt_nr,FLT_DT,FK_PSGR_ID,STATUS);
CREATE index idx_1_2_3 on FNF(FLT_DT,SCH_DEP_CD);优化后执行计划：
#NSET2: [821, 385, 596]
2 #PIPE2: [821, 385, 596]
3 #PRJT2: [821, 385, 596]; exp_num(4), is_atom(FALSE)
4 #SORT3: [821, 385, 596]; key_num(1), is_distinct(FALSE), top_flag(0), is_adaptive(0)
5 #SLCT2: [820, 385, 596]; LI.FK_PSGR_ID = PI.PSGR_ID
6 #NEST LOOP INNER JOIN2: [820, 385, 596]; [with var]
7 #HASH2 INNER JOIN: [2, 385, 470]; KEY_NUM(4); KEY(FI.ACT_DEP_CD=LI.DEP_ARP_CD AND FI.FLT_DT=LI.FLT_DT AND FI.V1=LI.ALN_CD AND FI.V2=LI.FLT_NR) KEY_NULL_EQU(0, 0, 0, 0)
8 #NEST LOOP INDEX JOIN2: [2, 385, 470]
9 #ACTRL: [2, 385, 470];
10 #PRJT2: [1, 385, 235]; exp_num(5), is_atom(FALSE)
11 #RN: [1, 385, 235]
12 #BLKUP2: [1, 385, 235]; IDX_FLIGHT_INFO02(FNF)
13 #SSEK2: [1, 385, 235]; scan_type(ASC), IDX_FLIGHT_INFO02(FNF), scan_range[(exp_cast(2024-04-01),'CAN',min),(exp_cast(2024-04-01),'CAN',max))
14 #SSEK2: [1, 1, 235]; scan_type(ASC), IDX_1_2_3_LI(LNF as LI), scan_range[(FI.V1,FI.ACT_DEP_CD,FI.V2,FI.FLT_DT,min,min),(FI.V1,FI.ACT_DEP_CD,FI.V2,FI.FLT_DT,max,max))
15 #SSCN: [989, 6461936, 235]; IDX_1_2_3_LI(LNF as LI); btr_scan(1)
16 #PRJT2: [2, 1, 126]; exp_num(3), is_atom(FALSE)
17 #DISTINCT: [2, 1, 126]
18 #PRJT2: [1, 2, 126]; exp_num(3), is_atom(FALSE)
19 #UNION ALL: [1, 2, 126]
20 #PRJT2: [1, 1, 126]; exp_num(3), is_atom(FALSE)
21 #SLCT2: [1, 1, 126]; NOT(PNF.HV_TYPE IS NULL)
22 #BLKUP2: [1, 1, 126]; INDEX33555482(PNF)
23 #SSEK2: [1, 1, 126]; scan_type(ASC), INDEX33555482(PNF), scan_range[var4,var4]
24 #PRJT2: [1, 1, 126]; exp_num(3), is_atom(FALSE)
25 #HASH RIGHT SEMI JOIN2: [1, 1, 126]; n_keys(1) KEY(DMTEMPVIEW_889228539.colname=PNF.CLAZZ) KEY_NULL_EQU(0)
26 #CONST VALUE LIST: [1, 7, 48]; row_num(7), col_num(1)
27 #BLKUP2: [1, 1, 126]; INDEX33555482(PNF)
28 #SSEK2: [1, 1, 126]; scan_type(ASC), INDEX33555482(PNF), scan_range[var4,var4]
29 #SPL2: [1, 1, 96]; key_num(1), spool_num(0), is_atom(TRUE), has_var(1), sites(-)
30 #PRJT2: [1, 1, 96]; exp_num(1), is_atom(TRUE)
31 #BLKUP2: [1, 6, 96]; INDEX33555479(OQ)
32 #SLCT2: [1, 6, 96]; var3 = exp11
33 #SSCN: [1, 6, 96]; INDEX33555479(OQ_FLT_INFO as OQ); btr_scan(1)执行时间：
通过改写+创建索引优化后，能做到像ORACLE这样，真"秒出结果"。😺
堆表和索引组织表的区别还是蛮大的，以前的老系统，业务SQL写得烂，用堆表跑问题不大，Oracle cbo算法牛逼也抗得住。
**但是现在很多国产数据库都是使用索引组织表（IOT表 ），例如 **OB、DM、TIDB 等国产数据库。
由于IOT表的特性在使用场景来说，对些老系统来说并不友好（老系统业务设计随意、业务逻辑较多在数据库层面实现），所以会产生很多性能问题： ORACLE 的索引都迁移到国产数据库了，性能还这么差，为什么没用上原来的索引啥的，等等诸如此类的问题。
要做国产化适配改造，并不能满足数据库功能、特性上的实现，业务模型也要配合整体来进行改造。
感谢各位读者同学能看到这里，如果有一些奇葩的SQL问题也可以联系我。🥰🥰** 🥰**