我使用下面的SQL语句创建了一个DB2视图。有人可以帮助我如何提高这个视图性能，因为它有时运行缓慢。
我注意到的一件事是，它第一次运行缓慢，但随后的运行，它加快了速度。我用可视化解释进行了分析，但是当它运行缓慢时，我没有看到任何索引建议。所以我不知道如何优化这个
-- Generate SQL
-- Version: V7R4M0 190621
-- Generated on: 02/09/21 03:08:31
-- Relational Database: BIGBLUE
-- Standards Option: Db2 for i
CREATE VIEW IESQAFILE.PSCMPORDVW
AS
WITH INPROGRESS AS
(
SELECT
DIODR#
, DIDISP
, DIUNIT
, DISTST
, DIAPRV
, DIETAD
, DITRLR AS TRAILER_ID
, DIDR1
, DIETAT
FROM
IESQAFILE.LOAD
WHERE
DIETAD <> 0
AND DIETAT <> '0000'
ORDER BY
1
)
, STOPGROUP AS
(
SELECT
SOORD STOPORDER
, COUNT(*) STOPSREMAIN
, MIN(SOSTP#) NEXTSTOP
, MAX(SOAPPR) APPTREQ
FROM
PAVT.STOP
INNER JOIN
INPROGRESS
ON
DIODR# = SOORD
WHERE
SOARDT = 0
GROUP BY
SOORD
ORDER BY
1
)
, STOPAPPTS AS
(
SELECT
SOORD APPTORDER
, SOCUST STOPCUST
, SOEDA ETADATE
, SOETA ETATIME
, SOADT1 EARLYDATE
, SOATM1 EARLYTIME
, SOADT2 LATEDATE
, SOATM2 LATETIME
, SOCTYC NEXTCITY
, SOSTP# APPTSTOP
, SOST NEXTSTATE
FROM
IESQAFILE.STOPOFF
INNER JOIN
STOPGROUP
ON
STOPORDER = SOORD
AND NEXTSTOP = SOSTP#
)
SELECT
ORDER_NUMBER
, SHIPPER_ID
, SHIPPER_NAME
, SHIPPER_ADDRESS_1
, SHIPPER_ADDRESS_2
, SHIPPER_CITY
, SHIPPER_ST
, SHIPPER_ZIP
, SHIPPER_ZIP_EXT
, LOAD_AT_ID
, LOAD_AT_NAME
, LOAD_AT_ADDRESS_1
, LOAD_AT_ADDRESS_2
, LOAD_AT_CITY
, LOAD_AT_ST
, LOAD_AT_ZIP
, LOAD_AT_ZIP_EXT
, LOAD_AT_LATITUDE
, LOAD_AT_LONGITUDE
, EARLY_PU_DATE_TIME
, LATE_PU_DATE_TIME
, EARLY_DELV_DATE_TIME
, EST_REVENUE
, ORDER_DIV
, CONSIGNEE_ID
, CONSIGNEE_NAME
, CONSIGNEE_ADDRESS_1
, CONSIGNEE_ADDRESS_2
, CONSIGNEE_CITY
, CONSIGNEE_ST
, CONSIGNEE_ZIP
, CONSIGNEE_ZIP_EXT
, CONSIGNEE_LATITUDE
, CONSIGNEE_LONGITUDE
, TRAILER_TYPE
, ORDER_MESSAGE
, ADDITIONAL_STOPS
, CMDTY_CODE
, CMDTY_DESCRIPTION
, ORDER_MILES
, ORDER_WGT
, ORIGIN_CITY_CODE
, ORIGIN_CITY
, ORIGIN_ST
, DEST_CITY_CODE
, DEST_CITY_NAME
, DEST_ST
, PICK_UP_AREA
, PLAN_INFO
, NUMBER_LDS
, NUMBER_DISP
, SHIP_DATE_TIME
, NEW_PICKUP_AREA
, EQUIPMENT_NUMBER
, APPT_REQ
, APPT_MADE
, PRE_T_SEQ
, PRE_T_AREA
, LOAD_DISPATCHED
, CUST_SERV_REP
, NEGOTIATIONS
,
(
CASE
WHEN UNUNIT IS NOT NULL
THEN UNUNIT
ELSE ' '
END
)
UNIT_DISPATCHED
,
(
CASE
WHEN UNSUPR IS NOT NULL
THEN UNSUPR
ELSE ' '
END
)
DRIVER_MGR_CODE
, COALESCE(SUPNAM, ' ') DRIVER_MGR_NAME
,
(
CASE
WHEN UNFMGR IS NOT NULL
THEN UNFMGR
ELSE ' '
END
)
FLEET_MGR_CODE
, COALESCE(FLTNAM,' ') FLEET_MGR_NAME
,
(
CASE
WHEN UNTRL1 IS NOT NULL
THEN UNTRL1
ELSE ' '
END
)
TRAILER_ID,
DIDISP DISPATCH_NUMBER,
(COALESCE(BCMCNEW, ' ')) FED_MC_ID,
DIUNIT DISPATCHED_UNIT,
CASE
WHEN UNETAD <> 0
AND UNETAT = ''
THEN SMIS.CVTDATETIM(CHAR(UNETAD),'0000', (
SELECT
SUBSTR(DATA_AREA_VALUE, 1109, 2) AS TIMEZONE
FROM
TABLE(QSYS2.DATA_AREA_INFO('COMPAN', '*LIBL'))
)
)
WHEN UNETAD <> 0
THEN SMIS.CVTDATETIM(CHAR(UNETAD),UNETAT, (
SELECT
SUBSTR(DATA_AREA_VALUE, 1109, 2) AS TIMEZONE
FROM
TABLE(QSYS2.DATA_AREA_INFO('COMPAN', '*LIBL'))
)
)
WHEN UNETAD = 0
THEN '0000-00-00T00:00:00-00:00'
END AS ETA_DATE_TIME,
NEXTSTOP , CASE
WHEN SOARDT <> 0
AND SOARTM = ''
THEN SMIS.CVTDATETIM(CHAR(SOARDT),'0000', (
SELECT
SUBSTR(DATA_AREA_VALUE, 1109, 2) AS TIMEZONE
FROM
TABLE(QSYS2.DATA_AREA_INFO('COMPAN', '*LIBL'))
)
)
WHEN SOARDT <> 0
THEN SMIS.CVTDATETIM(CHAR(SOARDT),SOARTM, (
SELECT
SUBSTR(DATA_AREA_VALUE, 1109, 2) AS TIMEZONE
FROM
TABLE(QSYS2.DATA_AREA_INFO('COMPAN', '*LIBL'))
)
)
WHEN SOARDT = 0
THEN '0000-00-00T00:00:00-00:00'
END AS STOP_ARRIVAL_DATE_TIME
, CASE
WHEN SOLUDT <> 0
AND SOLUTM = ''
THEN SMIS.CVTDATETIM(CHAR(SOLUDT),'0000', (
SELECT
SUBSTR(DATA_AREA_VALUE, 1109, 2) AS TIMEZONE
FROM
TABLE(QSYS2.DATA_AREA_INFO('COMPAN', '*LIBL'))
)
)
WHEN SOLUDT <> 0
THEN SMIS.CVTDATETIM(CHAR(SOLUDT),SOLUTM, (
SELECT
SUBSTR(DATA_AREA_VALUE, 1109, 2) AS TIMEZONE
FROM
TABLE(QSYS2.DATA_AREA_INFO('COMPAN', '*LIBL'))
)
)
WHEN SOLUDT = 0
THEN '0000-00-00T00:00:00-00:00'
END AS STOP_DEPART_DATE_TIME
, ORBAMT ORDER_INV_AMT
, ORARST AR_STATUS_FLAG
, DISTST SETTLEMENT_FLAG
, DIAPRV APPROVED_FOR_PAY
, BCCARR CARRIER_CODE
, BCNAME CARRIER_NAME
, BCADDR CARRIER_ADDRESS_1
, BCADR2 CARRIER_ADDRESS_2
, BCCITY CARRIER_CITY
, BCST CARRIER_ST
, BCZIP CARRIER_ZIP
FROM
INPROGRESS
INNER JOIN
IESQAFILE.PSMAINORVW A
ON
DIODR# = ORDER_NUMBER
AND DIDISP = NUMBER_DISP
AND
(
SUBSTR(ORDER_NUMBER, 1, 2) <> 'DH'
AND SUBSTR(ORDER_NUMBER, 1, 1) <> 'M'
)
LEFT OUTER JOIN
IESQAFILE.STOPOFF
ON
DIODR# = SOORD
AND SOSTP# = 90
LEFT OUTER JOIN
IESQAFILE.LMCARR
ON
DIUNIT = BCCARR
LEFT OUTER JOIN
IESQAFILE.MMILES
ON
MMORD# = DIODR#
AND MMRECTYPE = 'D'
AND MMDSP# = DIDISP
EXCEPTION JOIN
IESQAFILE.ORDBILL B
ON
B.ORODR# = DIODR#
AND B.ORSEQ = ' '
AND ORARST = '1'
LEFT OUTER JOIN
STOPGROUP
ON
STOPORDER = DIODR#
LEFT OUTER JOIN
STOPAPPTS
ON
APPTORDER = STOPORDER
AND APPTSTOP = NEXTSTOP
LEFT OUTER JOIN
IESQAFILE.UNITS
ON
UNUNIT = DIUNIT
AND UNORD# = ORDER_NUMBER
LEFT OUTER JOIN
IESQAFILE.SUPMAST
ON
SUPCDE = UNSUPR
LEFT OUTER JOIN
IESQAFILE.FLTMAST
ON
UNFMGR = FLTCDE
WHERE
DIETAD <> 0
AND DIETAT <> '0000'
RCDFMT PSCMPORDVW ;
没有看到可视化解释(VE)数据(在这里不是很容易共享的东西)给你一个"魔术棒";答案不太可能。
我很惊讶你没有看到任何索引建议。但即便如此，你也应该能够比较"快速"one_answers"快速"之间的VE数据。和";slow"运行查看差异在哪里。确保你有"视图"- "高亮" "昂贵的图标"- "…打开。还要检查"选项"——>"属性详细信息"one_answers"Options"—;图Detail"…
使用最新版本(1.1.8.6)的访问客户端解决方案(ACS)总是一个好主意，其中包括运行SQL脚本&组件。
一些事情跳出来，包含聚合(计数，最小，最大)的编码向量索引(EVI)可能会在这里有所帮助…
select soord stoporder
,count(*) stopsremain
,min(sostp#) nextstop
,max(soappr) apptreq
from pavt.stop
和索引(或两个)与派生列substr(order_number,....)可能在这里有帮助:
from inprogress
inner join iesqafile.psmainorvw a
on diodr# = order_number
and didisp = number_disp
and (substr(order_number, 1, 2) <> 'DH'
and substr(order_number, 1, 1) <> 'M')
将语句的各个部分分解，并尽可能地优化各个部分。希望当你把它重新组合在一起时，收益仍然存在。
需要记住的一点是，视图与性能无关。它既不会帮助也不会损害性能。
您没有给出如何访问视图的示例，但是您考虑过使用用户定义表函数(UDTF)吗?当查询引擎尝试下推选择标准时，UDTF的参数使您可以轻松地显式包含选择标准。您甚至可能受益于将语句封装在UDTF中，并在UDTF上构建视图。您可以看到message_queue_info视图的示例(通过生成SQL源)&IBM提供的QSYS2中的UDTF。