我有一个查询，可以从视图和更多表中进行选择。
当我按原样执行此查询时-性能很差。
当我使用视图的查询并使用iframe将其添加到外部查询中时，它的运行速度非常快。
我的测试表明，问题不在于视图的查询本身，而在于优化器将视图数据与其他数据结合在一起的方式。
对此问题的解释是什么？
由于30K个字符的限制，选择查询中缺少一些字段。
WITH CLAUSE视图查询（性能不佳）
--View:
CREATE OR REPLACE VIEW DWH.CC_MC_VIEW AS
SELECT /*+ full(E) */
DISTINCT/* a lot of fields */
FROM dwh.t2002_merkazei_tamhir_cur a
LEFT JOIN dwh.allovdim b
ON a.oved_achrai_char = TO_CHAR(b.mis_oved)
AND a.company = b.company
LEFT JOIN dwh.t2003_kodei_merkazei_tamhir h
ON h.year = TO_CHAR(SYSDATE-28,'yyyy')
AND h.erech = a.c01_agaf
AND h.company = A.company
AND h.amuda = '01'
LEFT JOIN dwh.t2003_kodei_merkazei_tamhir g
ON g.erech = a.c03_minhal_rb
AND g.amuda = '03'
AND g.year = TO_CHAR(SYSDATE-28,'yyyy')
AND g.company = A.company
LEFT JOIN DWH_COMPANIES E
ON A.COMPANY = E.COM_COMPANY_CODE
LEFT JOIN dwh.t2003_kodei_merkazei_tamhir d
ON d.erech = a.c02_minhalhativa
AND d.amuda = '02'
AND D.year = TO_CHAR(SYSDATE-28,'yyyy')
AND A.COMPANY = D.COMPANY
LEFT JOIN dwh.allovdim c
ON d.oved_achrai = c.mis_oved
AND d.company = c.company
LEFT JOIN DWH_COMPANIES F
ON D.COMPANY = F.COM_COMPANY_CODE
WHERE KOD_SGIRA = 1;
说明视图计划（效果不佳）
(SELECT ROUND(dwh.plm_docdelivery.RELEASEDDATE-dwh.plm_docdelivery.PROCESSSTARTDATE),
ROUND(sysdate -dwh.plm_docdelivery.PROCESSSTARTDATE),
dwh.plm_docdelivery.*,
dwh.cc_mc_view.*,
dwh.plm_programs.*,
FROM dwh.plm_docdelivery,
DWH.PLM_PROGRAMS,
dwh.cc_mc_view,
dwh.allovdim ENG_OWNER,
dwh.plm_last_rev
WHERE
(
dwh.plm_docdelivery.PROGRAMNUMBER=dwh.plm_programs.PROGRAMNUMBER
AND dwh.plm_docdelivery.COMPANY=dwh.plm_programs.COMPANY
AND dwh.plm_docdelivery.LOGISTICCOMPANY=dwh.plm_programs.LOGISTICCOMPANY
)
AND
(
dwh.plm_docdelivery.ENGOWNERID= ENG_OWNER.EMP_ID(+)
)
AND
(
dwh.cc_mc_view.MERKAZ_TAMHIR(+)=ENG_OWNER.MIS_TAMH
AND dwh.cc_mc_view.COMPANY(+) =ENG_OWNER.COMPANY
)
AND
(
dwh.plm_last_rev.COMPANY=dwh.plm_docdelivery.COMPANY
AND dwh.plm_last_rev.LOGISTICCOMPANY=dwh.plm_docdelivery.LOGISTICCOMPANY
AND dwh.plm_last_rev.PROGRAMNUMBER=dwh.plm_docdelivery.PROGRAMNUMBER
AND dwh.plm_last_rev.DOCUMENT=dwh.plm_docdelivery.DOCUMENT
)
AND
(ENG_OWNER.COMPANY<>'SOL')
AND
(dwh.plm_docdelivery.PROGRAMNUMBER IN ('X395','X419','X422','X379','X454','X372','X308', 'X394','X426','X433','X423','X391','X391A','X393','X490','X510','X460','X466A','X466B', 'X466C','X448','T622','T610','X461','X470','X520','X436','X560','D308','X922B','X922','X435', 'X494','X402','X995SP','X493','X481','X990','T799')
AND
(dwh.plm_docdelivery.CDRLTYPE <> 'SDRL'
OR dwh.plm_docdelivery.CDRLTYPE IS NULL)
AND dwh.plm_last_rev.LAST_REV = dwh.plm_docdelivery.DOCUMENTREVISION
AND((dwh.plm_docdelivery.AUTHORDATE <= '16-07-2017 00:00:00'
AND(dwh.plm_docdelivery.STATUS IN ( '(Freeze)','(Released)' )
OR dwh.plm_docdelivery.STATUS IS NULL))
OR dwh.plm_docdelivery.RELEASEDDATE IS NOT NULL)
AND dwh.plm_programs.COMPANY IN ('ESL','TCL'))
MINUS
SELECT ROUND(dwh.plm_docdelivery.RELEASEDDATE-dwh.plm_docdelivery.PROCESSSTARTDATE),
ROUND(sysdate -dwh.plm_docdelivery.PROCESSSTARTDATE),
dwh.plm_docdelivery.STATUS,
dwh.plm_docdelivery.SIGNERSLEFT,
dwh.plm_docdelivery.RELEASEDDATE,
dwh.plm_docdelivery.PROGRAMNUMBER,
dwh.plm_programs.PROGRAMNAME,
dwh.cc_mc_view.MINHALHATIVA,
TO_CHAR(dwh.plm_docdelivery.PLANNEDVALUE)
||
dwh.plm_docdelivery.TIMEUNIT
||
' '
||
CASE
WHEN dwh.plm_docdelivery.PLANNEDRELATION='After'
THEN '+'
WHEN dwh.plm_docdelivery.PLANNEDRELATION='Before'
THEN '-'
ELSE ''
END
||
dwh.plm_docdelivery.CDRLGATENAME,
ENG_OWNER.MISHPAHA,
ENG_OWNER.MISHPAHA_ENG,
ENG_OWNER.PRATI,
ENG_OWNER.PRATI_ENG,
dwh.plm_docdelivery.ENGOWNERID,
dwh.plm_docdelivery.ENGDISCIPLINE,
dwh.cc_mc_view.ACHRAI_HATIVA_NAME,
dwh.cc_mc_view.OVED_ACHRAI_HATIVA_FULL,
dwh.cc_mc_view.ACHRAI_MT_NAME,
dwh.cc_mc_view.OVED_ACHRAI_MT_FULL,
dwh.plm_docdelivery.DOCUMENTREVISION,
dwh.plm_docdelivery.DOCUMENTNAME,
dwh.plm_docdelivery.DOCUMENT,
dwh.plm_docdelivery.DELIVERY,
dwh.plm_docdelivery.CURRENTUSER ,
dwh.cc_mc_view.MERKAZ_TAMHIR,
dwh.plm_docdelivery.CDRLTYPE,
dwh.plm_docdelivery.CDRL,
dwh.plm_docdelivery.AUTHORDATE,
dwh.plm_docdelivery.DOC_REV_CREATION_DATE,
dwh.plm_docdelivery.DELIVERY_CREATION_DATE,
dwh.plm_docdelivery.GATEORIGINALDATE,
dwh.plm_programs.STATUS_DATE,
dwh.plm_docdelivery.ProcedureName,
dwh.plm_last_rev.LAST_REV,
dwh.plm_programs.COMPANY
FROM dwh.plm_docdelivery,
DWH.PLM_PROGRAMS,
dwh.cc_mc_view,
dwh.allovdim ENG_OWNER,
dwh.plm_last_rev
WHERE
(dwh.plm_docdelivery.PROGRAMNUMBER =dwh.plm_programs.PROGRAMNUMBER
AND dwh.plm_docdelivery.COMPANY =dwh.plm_programs.COMPANY
AND dwh.plm_docdelivery.LOGISTICCOMPANY=dwh.plm_programs.LOGISTICCOMPANY)
AND
(dwh.plm_docdelivery.ENGOWNERID= ENG_OWNER.EMP_ID(+))
AND
(dwh.cc_mc_view.MERKAZ_TAMHIR(+)=ENG_OWNER.MIS_TAMH
AND dwh.cc_mc_view.COMPANY(+) =ENG_OWNER.COMPANY)
AND
(dwh.plm_last_rev.COMPANY =dwh.plm_docdelivery.COMPANY
AND dwh.plm_last_rev.LOGISTICCOMPANY=dwh.plm_docdelivery.LOGISTICCOMPANY
AND dwh.plm_last_rev.PROGRAMNUMBER =dwh.plm_docdelivery.PROGRAMNUMBER
AND dwh.plm_last_rev.DOCUMENT =dwh.plm_docdelivery.DOCUMENT)
AND
(ENG_OWNER.COMPANY<>'SOL')
AND
(dwh.plm_docdelivery.PROGRAMNUMBER IN ('X395','X419','X422','X379','X454','X372','X308', 'X394','X426','X433','X423','X391','X391A','X393','X490','X510','X460','X466A','X466B', 'X466C','X448','T622','T610','X461','X470','X520','X436','X560','D308','X922B','X922','X435', 'X494','X402','X995SP','X493','X481','X990','T799')
AND dwh.plm_docdelivery.DELIVERY IS NOT NULL
AND dwh.plm_docdelivery.DOCUMENT IS NULL
AND dwh.plm_programs.COMPANY IN ('CMP1','CMP2')))
带有WITH子句的变体（效果好）
Plan hash value: 822592127
-------------------------------------------------------------------------------------------------------------------------
| Id | Operation| Name | Rows | Bytes | Cost (%CPU)| Time |
-------------------------------------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 57 | 52896 | 32848 (2)| 00:01:39 |
| 1 | MINUS | | | | | |
| 2 | SORT UNIQUE | | 57 | 26448 | 16424 (2)| 00:00:50 |
| 3 | NESTED LOOPS OUTER | | 57 | 26448 | 16423 (2)| 00:00:50 |
| 4 | NESTED LOOPS | | 20 | 5540 | 14146 (3)| 00:00:43 |
|* 5 | HASH JOIN | | 20 | 4660 | 14106 (3)| 00:00:43 |
|* 6 | TABLE ACCESS FULL | PLM_LAST_REV | 50 | 1300 | 13959 (3)| 00:00:42 |
| 7 | NESTED LOOPS | | 798 | 161K| 147 (2)| 00:00:01 |
| 8 | NESTED LOOPS | | 798 | 161K| 147 (2)| 00:00:01 |
|* 9 | TABLE ACCESS FULL| PLM_PROGRAMS | 44 | 1496 | 14 (8)| 00:00:01 |
|* 10 | INDEX RANGE SCAN | IDX_DELIVERY_1 | 1 | | 2 (0)| 00:00:01 |
|* 11 | TABLE ACCESS BY INDEX ROWID | PLM_DOCDELIVERY | 18 | 3114 | 3 (0)| 00:00:01 |
| 12 | TABLE ACCESS BY INDEX ROWID | ALLOVDIM | 1 | 44 | 2 (0)| 00:00:01 |
|* 13 | INDEX RANGE SCAN | ALLOVDIM_I_EMP_CMP | 1 | | 1 (0)| 00:00:01 |
| 14 | VIEW PUSHED PREDICATE| CC_MC_VIEW | 1 | 187 | 114 (2)| 00:00:01 |
| 15 | SORT UNIQUE | | 1 | 217 | 114 (2)| 00:00:01 |
|* 16 | FILTER | | | | | |
| 17 | NESTED LOOPS OUTER| | 1 | 217 | 113 (1)| 00:00:01 |
| 18 | NESTED LOOPS OUTER | | 1 | 173 | 97 (2)| 00:00:01 |
|* 19 | HASH JOIN OUTER | | 1 | 167 | 96 (2)| 00:00:01 |
| 20 | NESTED LOOPS OUTER | | 1 | 161 | 48 (0)| 00:00:01 |
| 21 | NESTED LOOPS OUTER | | 1 | 117 | 46 (0)| 00:00:01 |
| 22 | NESTED LOOPS OUTER | | 1 | 90 | 32 (0)| 00:00:01 |
| 23 | NESTED LOOPS OUTER | | 1 | 65 | 18 (0)| 00:00:01 |
|* 24 | TABLE ACCESS BY INDEX ROWID| T2002_MERKAZEI_TAMHIR_CUR | 1 | 40 | 4 (0)| 00:00:01 |
|* 25 |INDEX RANGE SCAN | T2002_MERKAZEI_TAMHIR_CUR_I1 | 3 | | 1 (0)| 00:00:01 |
| 26 | TABLE ACCESS BY INDEX ROWID| T2003_KODEI_MERKAZEI_TAMHIR | 1 | 25 | 14 (0)| 00:00:01 |
|* 27 |INDEX RANGE SCAN | T2003_K_MT97_Y_AE_I | 1 | | 13 (0)| 00:00:01 |
| 28 | TABLE ACCESS BY INDEX ROWID | T2003_KODEI_MERKAZEI_TAMHIR | 1 | 25 | 14 (0)| 00:00:01 |
|* 29 | INDEX RANGE SCAN | T2003_K_MT97_Y_AE_I | 1 | | 13 (0)| 00:00:01 |
| 30 | TABLE ACCESS BY INDEX ROWID | T2003_KODEI_MERKAZEI_TAMHIR | 1 | 27 | 14 (0)| 00:00:01 |
|* 31 | INDEX RANGE SCAN | T2003_K_MT97_Y_AE_I | 1 | | 13 (0)| 00:00:01 |
| 32 | TABLE ACCESS BY INDEX ROWID | ALLOVDIM | 1 | 44 | 2 (0)| 00:00:01 |
|* 33 | INDEX RANGE SCAN | ALLOVDIM_I_CMP_MIS | 1 | | 1 (0)| 00:00:01 |
|* 34 | TABLE ACCESS FULL | DWH_COMPANIES| 1 | 6 | 47 (0)| 00:00:01 |
| 35 | TABLE ACCESS BY INDEX ROWID | DWH_COMPANIES| 1 | 6 | 1 (0)| 00:00:01 |
|* 36 | INDEX UNIQUE SCAN | COMP_IDX1 | 1 | | 0 (0)| 00:00:01 |
| 37 | TABLE ACCESS BY INDEX ROWID | ALLOVDIM | 1 | 44 | 16 (0)| 00:00:01 |
|* 38 | INDEX RANGE SCAN| ALLOVDIM_I_CMP_MIS | 1 | | 15 (0)| 00:00:01 |
| 39 | SORT UNIQUE | | 57 | 26448 | 16424 (2)| 00:00:50 |
| 40 | NESTED LOOPS OUTER | | 57 | 26448 | 16423 (2)| 00:00:50 |
| 41 | NESTED LOOPS | | 20 | 5540 | 14145 (3)| 00:00:43 |
|* 42 | HASH JOIN | | 20 | 4660 | 14105 (3)| 00:00:43 |
|* 43 | TABLE ACCESS FULL | PLM_LAST_REV | 50 | 1300 | 13959 (3)| 00:00:42 |
| 44 | NESTED LOOPS | | 64 | 13248 | 146 (1)| 00:00:01 |
| 45 | NESTED LOOPS | | 64 | 13248 | 146 (1)| 00:00:01 |
|* 46 | TABLE ACCESS FULL| PLM_PROGRAMS | 44 | 1496 | 14 (8)| 00:00:01 |
|* 47 | INDEX RANGE SCAN | IDX_DELIVERY_1 | 1 | | 2 (0)| 00:00:01 |
|* 48 | TABLE ACCESS BY INDEX ROWID | PLM_DOCDELIVERY | 1 | 173 | 3 (0)| 00:00:01 |
| 49 | TABLE ACCESS BY INDEX ROWID | ALLOVDIM | 1 | 44 | 2 (0)| 00:00:01 |
|* 50 | INDEX RANGE SCAN | ALLOVDIM_I_EMP_CMP | 1 | | 1 (0)| 00:00:01 |
| 51 | VIEW PUSHED PREDICATE| CC_MC_VIEW | 1 | 187 | 114 (2)| 00:00:01 |
| 52 | SORT UNIQUE | | 1 | 217 | 114 (2)| 00:00:01 |
|* 53 | FILTER | | | | | |
| 54 | NESTED LOOPS OUTER| | 1 | 217 | 113 (1)| 00:00:01 |
| 55 | NESTED LOOPS OUTER | | 1 | 173 | 97 (2)| 00:00:01 |
|* 56 | HASH JOIN OUTER | | 1 | 167 | 96 (2)| 00:00:01 |
| 57 | NESTED LOOPS OUTER | | 1 | 161 | 48 (0)| 00:00:01 |
| 58 | NESTED LOOPS OUTER | | 1 | 117 | 46 (0)| 00:00:01 |
| 59 | NESTED LOOPS OUTER | | 1 | 90 | 32 (0)| 00:00:01 |
| 60 | NESTED LOOPS OUTER | | 1 | 65 | 18 (0)| 00:00:01 |
|* 61 | TABLE ACCESS BY INDEX ROWID| T2002_MERKAZEI_TAMHIR_CUR | 1 | 40 | 4 (0)| 00:00:01 |
|* 62 |INDEX RANGE SCAN | T2002_MERKAZEI_TAMHIR_CUR_I1 | 3 | | 1 (0)| 00:00:01 |
| 63 | TABLE ACCESS BY INDEX ROWID| T2003_KODEI_MERKAZEI_TAMHIR | 1 | 25 | 14 (0)| 00:00:01 |
|* 64 |INDEX RANGE SCAN | T2003_K_MT97_Y_AE_I | 1 | | 13 (0)| 00:00:01 |
| 65 | TABLE ACCESS BY INDEX ROWID | T2003_KODEI_MERKAZEI_TAMHIR | 1 | 25 | 14 (0)| 00:00:01 |
|* 66 | INDEX RANGE SCAN | T2003_K_MT97_Y_AE_I | 1 | | 13 (0)| 00:00:01 |
| 67 | TABLE ACCESS BY INDEX ROWID | T2003_KODEI_MERKAZEI_TAMHIR | 1 | 27 | 14 (0)| 00:00:01 |
|* 68 | INDEX RANGE SCAN | T2003_K_MT97_Y_AE_I | 1 | | 13 (0)| 00:00:01 |
| 69 | TABLE ACCESS BY INDEX ROWID | ALLOVDIM | 1 | 44 | 2 (0)| 00:00:01 |
|* 70 | INDEX RANGE SCAN | ALLOVDIM_I_CMP_MIS | 1 | | 1 (0)| 00:00:01 |
|* 71 | TABLE ACCESS FULL | DWH_COMPANIES| 1 | 6 | 47 (0)| 00:00:01 |
| 72 | TABLE ACCESS BY INDEX ROWID | DWH_COMPANIES| 1 | 6 | 1 (0)| 00:00:01 |
|* 73 | INDEX UNIQUE SCAN | COMP_IDX1 | 1 | | 0 (0)| 00:00:01 |
| 74 | TABLE ACCESS BY INDEX ROWID | ALLOVDIM | 1 | 44 | 16 (0)| 00:00:01 |
|* 75 | INDEX RANGE SCAN| ALLOVDIM_I_CMP_MIS | 1 | | 15 (0)| 00:00:01 |
解释WITH子句的计划
with CC as
(SELECT /*+full(E) */
DISTINCT/* a lot of fields */
FROM dwh.t2002_merkazei_tamhir_cur a
LEFT JOIN dwh.allovdim b
ON a.oved_achrai_char = TO_CHAR(b.mis_oved)
AND a.company = b.company
LEFT JOIN dwh.t2003_kodei_merkazei_tamhir h
ON h.year = TO_CHAR(SYSDATE-28,'yyyy')
AND h.erech = a.c01_agaf
AND h.company = A.company
AND h.amuda = '01'
LEFT JOIN dwh.t2003_kodei_merkazei_tamhir g
ON g.erech = a.c03_minhal_rb
AND g.amuda = '03'
AND g.year = TO_CHAR(SYSDATE-28,'yyyy')
AND g.company = A.company
LEFT JOIN DWH_COMPANIES E
ON A.COMPANY = E.COM_COMPANY_CODE
LEFT JOIN dwh.t2003_kodei_merkazei_tamhir d
ON d.erech = a.c02_minhalhativa
AND d.amuda = '02'
AND D.year = TO_CHAR(SYSDATE-28,'yyyy')
AND A.COMPANY = D.COMPANY
LEFT JOIN dwh.allovdim c
ON d.oved_achrai = c.mis_oved
AND d.company = c.company
LEFT JOIN DWH_COMPANIES F
on D.COMPANY = F.COM_COMPANY_CODE
WHERE KOD_SGIRA = 1
)
(
SELECT ROUND(dwh.plm_docdelivery.RELEASEDDATE-dwh.plm_docdelivery.PROCESSSTARTDATE),
ROUND(sysdate -dwh.plm_docdelivery.PROCESSSTARTDATE),
dwh.plm_docdelivery.*,
dwh.cc_mc_view.*,
dwh.plm_programs.*,
FROM dwh.plm_docdelivery,
DWH.PLM_PROGRAMS,
cc,
dwh.allovdim ENG_OWNER,
dwh.plm_last_rev
WHERE
(
dwh.plm_docdelivery.PROGRAMNUMBER=dwh.plm_programs.PROGRAMNUMBER
AND dwh.plm_docdelivery.COMPANY=dwh.plm_programs.COMPANY
AND dwh.plm_docdelivery.LOGISTICCOMPANY=dwh.plm_programs.LOGISTICCOMPANY
)
AND
(dwh.plm_docdelivery.ENGOWNERID= ENG_OWNER.EMP_ID(+))
AND
(cc.MERKAZ_TAMHIR(+)=ENG_OWNER.MIS_TAMH
AND cc.COMPANY(+) =ENG_OWNER.COMPANY)
AND
(dwh.plm_last_rev.COMPANY =dwh.plm_docdelivery.COMPANY
AND dwh.plm_last_rev.LOGISTICCOMPANY=dwh.plm_docdelivery.LOGISTICCOMPANY
AND dwh.plm_last_rev.PROGRAMNUMBER =dwh.plm_docdelivery.PROGRAMNUMBER
AND dwh.plm_last_rev.DOCUMENT =dwh.plm_docdelivery.DOCUMENT)
AND
(ENG_OWNER.COMPANY<>'SOL')
AND
(dwh.plm_docdelivery.PROGRAMNUMBER IN ('X395','X419','X422','X379','X454','X372','X308', 'X394','X426','X433','X423','X391','X391A','X393','X490','X510','X460','X466A','X466B', 'X466C','X448','T622','T610','X461','X470','X520','X436','X560','D308','X922B','X922','X435', 'X494','X402','X995SP','X493','X481','X990','T799')
AND
(dwh.plm_docdelivery.CDRLTYPE <> 'SDRL'
OR dwh.plm_docdelivery.CDRLTYPE IS NULL)
AND dwh.plm_last_rev.LAST_REV = dwh.plm_docdelivery.DOCUMENTREVISION
AND((dwh.plm_docdelivery.AUTHORDATE <= '16-07-2017 00:00:00'
AND(dwh.plm_docdelivery.STATUS IN ( '(Freeze)','(Released)' )
OR dwh.plm_docdelivery.STATUS IS NULL))
OR dwh.plm_docdelivery.RELEASEDDATE IS NOT NULL)
AND dwh.plm_programs.COMPANY IN ('ESL','TCL'))
MINUS
SELECT ROUND(dwh.plm_docdelivery.RELEASEDDATE-dwh.plm_docdelivery.PROCESSSTARTDATE),
ROUND(sysdate-dwh.plm_docdelivery.PROCESSSTARTDATE),
dwh.plm_docdelivery.STATUS,
dwh.plm_docdelivery.SIGNERSLEFT,
dwh.plm_docdelivery.RELEASEDDATE,
dwh.plm_docdelivery.PROGRAMNUMBER,
dwh.plm_programs.PROGRAMNAME,
cc.MINHALHATIVA,
TO_CHAR(dwh.plm_docdelivery.PLANNEDVALUE)
||
dwh.plm_docdelivery.TIMEUNIT
||
' '
||
CASE
WHEN dwh.plm_docdelivery.PLANNEDRELATION='After'
THEN '+'
WHEN dwh.plm_docdelivery.PLANNEDRELATION='Before'
THEN '-'
ELSE ''
END
||
dwh.plm_docdelivery.CDRLGATENAME,
ENG_OWNER.MISHPAHA,
ENG_OWNER.MISHPAHA_ENG,
ENG_OWNER.PRATI,
ENG_OWNER.PRATI_ENG,
dwh.plm_docdelivery.ENGOWNERID,
dwh.plm_docdelivery.ENGDISCIPLINE,
cc.ACHRAI_HATIVA_NAME,
cc.OVED_ACHRAI_HATIVA_FULL,
cc.ACHRAI_MT_NAME,
cc.OVED_ACHRAI_MT_FULL,
dwh.plm_docdelivery.DOCUMENTREVISION,
dwh.plm_docdelivery.DOCUMENTNAME,
dwh.plm_docdelivery.DOCUMENT,
dwh.plm_docdelivery.DELIVERY,
dwh.plm_docdelivery.CURRENTUSER ,
cc.MERKAZ_TAMHIR,
dwh.plm_docdelivery.CDRLTYPE,
dwh.plm_docdelivery.CDRL,
dwh.plm_docdelivery.AUTHORDATE,
dwh.plm_docdelivery.DOC_REV_CREATION_DATE,
dwh.plm_docdelivery.DELIVERY_CREATION_DATE,
dwh.plm_docdelivery.GATEORIGINALDATE,
dwh.plm_programs.STATUS_DATE,
dwh.plm_docdelivery.ProcedureName,
dwh.plm_last_rev.LAST_REV,
dwh.plm_programs.COMPANY
FROM dwh.plm_docdelivery,DWH.PLM_PROGRAMS,cc,dwh.allovdim ENG_OWNER,dwh.plm_last_rev
WHERE(dwh.plm_docdelivery.PROGRAMNUMBER=dwh.plm_programs.PROGRAMNUMBER
AND dwh.plm_docdelivery.COMPANY=dwh.plm_programs.COMPANY
AND dwh.plm_docdelivery.LOGISTICCOMPANY=dwh.plm_programs.LOGISTICCOMPANY)
AND(dwh.plm_docdelivery.ENGOWNERID=ENG_OWNER.EMP_ID(+))
AND(cc.MERKAZ_TAMHIR(+)=ENG_OWNER.MIS_TAMH
AND cc.COMPANY(+)=ENG_OWNER.COMPANY)
AND(dwh.plm_last_rev.COMPANY=dwh.plm_docdelivery.COMPANY
AND dwh.plm_last_rev.LOGISTICCOMPANY=dwh.plm_docdelivery.LOGISTICCOMPANY
AND dwh.plm_last_rev.PROGRAMNUMBER=dwh.plm_docdelivery.PROGRAMNUMBER
AND dwh.plm_last_rev.DOCUMENT=dwh.plm_docdelivery.DOCUMENT)
AND(ENG_OWNER.COMPANY<>'SOL')
AND(dwh.plm_docdelivery.PROGRAMNUMBER IN ('X395','X419','X422','X379','X454','X372','X308', 'X394','X426','X433','X423','X391','X391A','X393','X490','X510','X460','X466A','X466B', 'X466C','X448','T622','T610','X461','X470','X520','X436','X560','D308','X922B','X922','X435', 'X494','X402','X995SP','X493','X481','X990','T799')
AND dwh.plm_docdelivery.DELIVERY IS NOT NULL
AND dwh.plm_docdelivery.DOCUMENT IS NULL
AND dwh.plm_programs.COMPANY IN ('CMP1','CMP2')));
答案 0 :(得分：3)
“一般来说，我想知道为什么视图和视图之间有区别”
在调优中有非常普遍适用的规则。通常情况取决于具体情况。因此，您的情况相关，关键是第二个解释计划中的这一步骤：
TEMP TABLE TRANSFORMATION
基本上，调优连接表和视图的查询非常困难，因为优化器无法真正确定视图将返回多少行。就像这里所做的那样，这通常会导致一个糟糕的计划。如果您查看第一个计划，则优化器选择了VIEW PUSHED PREDICATE。这意味着它将为其他表中的每一行查询一次视图。两次，因为有了MINUS运算符。由于优化器将谓词推入视图查询（ENG_OWNER.MIS_TAMH, ENG_OWNER.COMPANY）中，因此它使用了一系列嵌套循环来执行视图的查询。对于大表，这可能是一项昂贵的操作。
因此，通过WITH子句，优化器可以查看一个查询中的所有表，并可以决定将子查询结果集具体化为临时表。临时表并不总是有效的，因为它们涉及到临时表空间的写入和读取，而且许多DBA都不会费心去适当地配置其表空间。但是，实现的最大优点是视图查询仅执行一次，并且（只要结果集足够小）读取一次并保存在内存中。
由于实现似乎可行，您可以使用提示。
代替从视图中获取整个查询的WITH子句with CC_MC_VIEW as (select /*+ materialize */
from dwh.CC_MC_VIEW )
select ...
答案 1 :(得分：1)
通常在Oracle上应该没有区别。 With子句可以是INLINEed或MATERIALIZEd。查看文档，了解如何使用这些提示。同样，可以修改将VIEW“嵌入”执行计划的方式。查看文档和搜索参数complex_view_merging / simple_view_merging。
您能做的最好的就是比较两者的执行计划。没有看到他们，没有人可以帮助您。从理论上讲，如果两种情况下Oracle优化器应返回相同的结果，则应生成相同的执行计划。
更新：在第二种情况下，视图已进行了材料化（请参见TEMP TABLE TRANSFORMATION）。 Oracle将VIEW查询上的内容存储到TEMP表空间中，并将其用于进一步的联接。从理论上讲，这应该比内联（第一种情况）要慢。
如@William INLINE / MATERIALIZE提示所指出的尚未正式记录。 不幸的是，其他参数也没有记载。 尝试使用sqlplus（不是SqlDeveloper）4x执行慢查询，并通过设置（全部4种组合/ true / false）更改CBO参数
alter session set "_complex_view_merging"=true;
alter session set "_simple_view_merging"=true;
看看会发生什么。并且可能值得尝试从VIEW定义中删除FULL提示。您永远不会知道您将如何使用该视图，将使用哪些谓词，因此可能不需要表DWH_COMPANIES上的“ FULL TABLE SCAN”。