使用IBM Access Client Solution（ACS）的Run SQL Scripts组件中的Visual Explain (VE)功能，可以显示查询在何处花费了时间以及建议的索引。
话虽如此，使用RRN（）通常是一个坏主意，这里使用它的方式非常可疑。
此外，使用公共表表达式（with MyCTE ...）的好处是，您可以通过添加一个select * from lastCte;来检查结果
所以在你的情况下，

WITH PREORDER AS
 (
 SELECT *
 FROM
 ORDERPAR
 )
 , TCALLORDER AS
 (
 SELECT
 TPODR#
 , TPAREA
 , TPSEQ#
 FROM
 "ORDER"
 INNER JOIN
 OPTPLANP
 ON
 ORODR# = TPODR#
 EXCEPTION JOIN
 OPPLAN
 ON
 OPORD# = TPODR#
 AND TPSEQ# = OPTCSQ
 )
 select * from tcallorder;

当您继续浏览CTE时，您可以看到VE计划是如何变化的。

您必须对查询进行结构化处理，以便有机会理解查询并对其进行故障排除。
运行strdbg命令。然后从STRSQL提示符运行查询。您应该在作业日志中看到“建议的访问路径”消息。
然后连续运行查询。第一个单独运行查询。然后运行查询1到2。然后运行查询1到3。重点是运行它们以查看瓶颈在哪里。

WITH PREORDER AS
 ( SELECT *  FROM ORDERPAR    ), 
TCALLORDER AS
( SELECT  TPODR#, TPAREA, TPSEQ#
  FROM    "ORDER"
  INNER JOIN  OPTPLANP
  ON      ORODR# = TPODR#
  EXCEPTION JOIN OPPLAN
  ON     OPORD# = TPODR# AND TPSEQ# = OPTCSQ
),
FIRSTEQUIPRRN AS
( SELECT OEORD# EQUIPORDER, MIN(RRN(A)) FIRSTROW
  FROM   OPEQUIP A
  GROUP BY OEORD#
  ORDER BY 1
),
FIRSTEQUIPROW AS
( SELECT OEORD#, OETRLR EQUIPMENTNUMBER
  FROM   FIRSTEQUIPRRN
  INNER JOIN OPEQUIP B
  ON    EQUIPORDER = OEORD# AND FIRSTROW = RRN(B)
),
STOPGROUP AS
( SELECT  SOORD STOPORDER, COUNT(*) STOPSREMAIN, MIN(SOSTP#) NEXTSTOP, MAX(SOAPPR) APPTREQ,
          MAX(SOAPTM) APPTMADE
  FROM    STOPOFF
  INNER JOIN "ORDER"
  ON      ORODR# = SOORD
  WHERE   SOARDT = 0
  GROUP BY SOORD
  ORDER BY 1
),
ORDERMILES AS
( SELECT  MMORD#, MMTOTAL
  FROM    MMILES
  WHERE   MMORD# IN ( SELECT ORODR#
                      FROM   "ORDER" )
          AND MMRECTYPE = 'O' AND MMDSP# = '00'
),
NEGCOUNT AS
( SELECT  COUNT(*) NEGOTIATIONS, BNORD#
  FROM    LMNEG
  GROUP BY BNORD#
)

SELECT   A.ORODR# ORDER_NUMBER, ORCUST SHIPPER_ID, CUSTMS.CUNAME SHIPPER_NAME,
         CUSTMS.CUBAD1 SHIPPER_ADDRESS_1, CUSTMS.CUBAD2 SHIPPER_ADDRESS_2, CUSTMS.CUBCTY SHIPPER_CITY, 
         CUSTMS.CUBST SHIPPER_ST, CUSTMS.CUBZIP SHIPPER_ZIP, CUSTMS.CUBZP2 SHIPPER_ZIP_EXT,
         ORLDAT LOAD_AT_ID, CUSTML.CUNAME LOAD_AT_NAME, CUSTML.CUBAD1 LOAD_AT_ADDRESS_1, CUSTML.CUBAD2 LOAD_AT_ADDRESS_2,
         CUSTML.CUBCTY LOAD_AT_CITY, CUSTML.CUBST LOAD_AT_ST, CUSTML.CUBZIP LOAD_AT_ZIP,
         CUSTML.CUBZP2 LOAD_AT_ZIP_EXT, MCCL.C#DECLATD LOAD_AT_LATITUDE, MCCL.C#DECLOND LOAD_AT_LONGITUDE,
         CASE WHEN ORPDAT <> 0 AND ORPTIM = ''
              THEN CVTDATETIM(CHAR(ORPDAT),'0000', CMCPUZ)
              WHEN ORPDAT <> 0
              THEN CVTDATETIM(CHAR(ORPDAT),ORPTIM, CMCPUZ)
              WHEN ORPDAT = 0
              THEN '0000-00-00T00:00:00-00:00' END AS EARLY_PU_DATE_TIME,
         CASE WHEN ORAPDT <> 0 AND ORAPTM = ''
              THEN CVTDATETIM(CHAR(ORAPDT),'0000', CMCPUZ)
              WHEN ORAPDT <> 0
              THEN CVTDATETIM(CHAR(ORAPDT),ORAPTM, CMCPUZ)
              WHEN ORAPDT = 0
              THEN '0000-00-00T00:00:00-00:00' END AS LATE_PU_DATE_TIME,
         CASE WHEN ORDDAT <> 0 AND ORDTIM = ''
              THEN CVTDATETIM(CHAR(ORDDAT),'0000',CMCPUZ)
              WHEN ORDDAT <> 0
              THEN CVTDATETIM(CHAR(ORDDAT),ORDTIM, CMCPUZ)
              WHEN ORDDAT = 0
              THEN '0000-00-00T00:00:00-00:00' END AS EARLY_DELV_DATE_TIME,
          ORESTR EST_REVENUE, A.ORDV# ORDER_DIV, ORCONS CONSIGNEE_ID, CUSTMC.CUNAME CONSIGNEE_NAME,
          CUSTMC.CUBAD1 CONSIGNEE_ADDRESS_1, CUSTMC.CUBAD2 CONSIGNEE_ADDRESS_2, CUSTMC.CUBCTY CONSIGNEE_CITY,
          CUSTMC.CUBST CONSIGNEE_ST, CUSTMC.CUBZIP CONSIGNEE_ZIP, CUSTMC.CUBZP2 CONSIGNEE_ZIP_EXT,
          MCCC.C#DECLATD CONSIGNEE_LATITUDE, MCCC.C#DECLOND CONSIGNEE_LONGITUDE, OREQTY TRAILER_TYPE,
          ORSPEC ORDER_MESSAGE, A.ORSTP# ADDITIONAL_STOPS, ORCOMC CMDTY_CODE, ORCOMD CMDTY_DESCRIPTION,
          (COALESCE(MMTOTAL, 0)) ORDER_MILES, ORWGT ORDER_WGT, OROCTY ORIGIN_CITY_CODE,
          CITYOR.CINAME ORIGIN_CITY, OROST ORIGIN_ST, ORDCTY DEST_CITY_CODE, CITYDEST.CINAME DEST_CITY_NAME,
          ORDST DEST_ST, ORARA PICK_UP_AREA, ORPDRV PLAN_INFO, ORLD# NUMBER_LDS, OR#DSP NUMBER_DISP,
          CASE WHEN ORSHDT <> 0 AND ORSHTM = ''
               THEN CVTDATETIM(CHAR(ORSHDT),'0000',CMCPUZ)
          WHEN ORSHDT <> 0
          THEN CVTDATETIM(CHAR(ORSHDT),ORSHTM,CMCPUZ)
          WHEN ORSHDT = 0
          THEN '0000-00-00T00:00:00-00:00'
          END AS SHIP_DATE_TIME,
          ORNWPK NEW_PICKUP_AREA, (COALESCE(EQUIPMENTNUMBER, ' ')) EQUIPMENT_NUMBER,
          (COALESCE(APPTREQ, 'N')) APPT_REQ, (COALESCE(APPTMADE, 'N')) APPT_MADE,
          (COALESCE(TPSEQ#, ' ')) PRE_T_SEQ, (COALESCE(TPAREA, ' ')) PRE_T_AREA, ORDSP# LOAD_DISPATCHED,
          CASE WHEN APPTREQ = ' ' AND APPTMADE = ' '
               THEN APPTMADE
               WHEN APPTREQ = 'N' AND APPTMADE = 'Y'
               THEN APPTMADE
               WHEN APPTREQ = 'Y' AND APPTMADE = 'Y'
               THEN 'Y'
               WHEN APPTREQ = 'N' AND APPTMADE = 'N'
               THEN APPTREQ
               WHEN APPTREQ = ' '  OR APPTMADE = ' '
               THEN 'N'
               ELSE 'N' END AVAPPTREQ,
         ORSTAT, ORPDAT, CUSTMS.CUSVRP CUST_SERV_REP, NEGOTIATIONS
FROM     SUBSIDIARY, "ORDER" A
LEFT OUTER JOIN  CUSTMAST CUSTMS
ON       ORCUST = CUSTMS.CUCODE
LEFT OUTER JOIN CUSTMAST CUSTML
ON       ORLDAT = CUSTML.CUCODE
LEFT OUTER JOIN CUSTMAST CUSTMC
ON       ORCONS = CUSTMC.CUCODE
LEFT OUTER JOIN MCCSTLLP MCCS
ON       ORCUST = MCCS.C#CODE
LEFT OUTER JOIN MCCSTLLP MCCL
ON       ORLDAT = MCCL.C#CODE
LEFT OUTER JOIN MCCSTLLP MCCC
ON       ORCONS = MCCC.C#CODE
LEFT OUTER JOIN CITIES CITYOR
ON       OROST = CITYOR.CIST AND OROCTY = CITYOR.CICTY
LEFT OUTER JOIN CITIES CITYDEST
ON       ORDST = CITYDEST.CIST AND ORDCTY = CITYDEST.CICTY
LEFT OUTER JOIN MMILES
ON       MMORD# = A.ORODR# AND MMRECTYPE = 'O' AND MMDSP# = '00'
LEFT OUTER JOIN FIRSTEQUIPROW
ON       A.ORODR# = OEORD#
LEFT OUTER JOIN STOPGROUP
ON       A.ORODR# = STOPORDER
EXCEPTION JOIN OPPLAN
ON       OPORD# = A.ORODR#
LEFT OUTER JOIN TCALLORDER
ON       TPODR# = A.ORODR#
LEFT OUTER JOIN NEGCOUNT
ON BNORD# = A.ORODR#
WHERE    ( ORSTAT <> 'C' )