Best Practices for SAP BI using DB2 9 for z/OS - IBM Redbooks

10.1 SQL efficiency for DSO
Queries against the DSO can be long and complicated. They usually involve
joins to one or more master data tables, as well as local predicates on the master
data tables and DSO. Understanding and analyzing your queries is an important
step in performance tuning.
In this section we illustrate a method that you can use to break down a query.
This kind of analysis is helpful in determining the requirements for indexing,
clustering, partitioning, and statistics collection. Without first breaking down and
simplifying the query, it is not possible to adequately understand these
requirements.
Figure 10-1 shows the query that we analyze in this section. It is a real-life
customer query.
ODS Query Example
SELECT "S____065" , "S____028" , "S____097" , "S____109" , "S____179" , "S____180" , "0ADVERTISNG" , "0G_APRABA" , "0G_ASTDPR" , "0G_AVTRGK" ,
"0G_AVVCDA" , "0G_AVVCDC" , "0G_AVVCHG" , "0G_AVVCTG" , "0G_AVVDED" , "0G_AVVFGT" , "0G_AVVFIX" , "0G_AVVINV" , "0G_AVVIWS" , "0G_AVVLST" ,
"0G_AVVMDS" , "0G_AVVORB" , "0G_AVVRET" , "0G_AVVROY" , "0G_AVVSRB" , "0G_AVVVLB" , "0G_AVVVOT" , "0G_AVVVRM" , "0G_AVVWHG" , 0G_QABSMG" ,
"0G_QVVTON" , "0G_QVVUOM" , "0SALES_CMSN" , "0SALES_MARK" , "1ROWCOUNT" , "ZCOGS" , "ZEXTREV" , "ZFRT_DED" , "ZGRMRGN" , "ZGRMRGN_F" ,
"ZGROSSSLS" , "ZG_AVVFTC" , "ZINTERDV" , "ZINTRADV" , "ZNETSALES" , "ZNETSLS_F" , "ZSLSDEDS" , "ZTOTDED_F" , "ZT_OTHDED" , "ZT_REBATE"
FROM ( SELECT "DB2A0001"."SID" AS "S____065" , "/BI0/SCURRENCY"."SID" AS "S____028" ,"A0001"."SID" AS "S____097" , "A0002"."SID" AS "S____109"
,"/BI0/SREFER_DOC"."SID" AS "S____179" , "/BI0/SREFER_ITM"."SID" AS "S____180" , SUM ( "/BIC/AZOSASALE00"."ADVERTISNG" ) AS "0ADVERTISNG" , SUM (
"/BIC/AZOSASALE00"."G_APRABA" ) AS "0G_APRABA" , SUM ( "/BIC/AZOSASALE00"."G_ASTDPR" ) AS "0G_ASTDPR" , SUM (
"/BIC/AZOSASALE00"."G_AVTRGK" ) AS "0G_AVTRGK" , SUM (“ /BIC/AZOSASALE00"."G_AVVCDA" ) AS "0G_AVVCDA" , SUM (
"/BIC/AZOSASALE00"."G_AVVCDC" ) AS "0G_AVVCDC" , SUM ( "/BIC/AZOSASALE00"."G_AVVCHG" ) AS "0G_AVVCHG" , SUM (
"/BIC/AZOSASALE00"."G_AVVCTG" ) AS "0G_AVVCTG" , SUM ( "/BIC/AZOSASALE00"."G_AVVDED" ) AS "0G_AVVDED" , SUM (
"/BIC/AZOSASALE00"."G_AVVFGT" ) AS "0G_AVVFGT" , SUM ( "/BIC/AZOSASALE00"."G_AVVFIX" ) AS "0G_AVVFIX" , SUM ( "/BIC/AZOSASALE00"."G_AVVINV" )
AS "0G_AVVINV" , SUM ( "/BIC/AZOSASALE00"."G_AVVIWS" ) AS "0G_AVVIWS" , SUM ( "/BIC/AZOSASALE00"."G_AVVLST" ) AS "0G_AVVLST" , SUM (
"/BIC/AZOSASALE00"."G_AVVMDS" ) AS "0G_AVVMDS" , SUM ( "/BIC/AZOSASALE00"."G_AVVORB" ) AS "0G_AVVORB" , SUM (
"/BIC/AZOSASALE00"."G_AVVRET" ) AS "0G_AVVRET" , SUM ( "/BIC/AZOSASALE00"."G_AVVROY" ) AS "0G_AVVROY" , SUM (
"/BIC/AZOSASALE00"."G_AVVSRB" ) AS "0G_AVVSRB" , SUM ( "/BIC/AZOSASALE00"."G_AVVVLB" ) AS "0G_AVVVLB" , SUM ( "/BIC/AZOSASALE00"."G_AVVVOT"
) AS "0G_AVVVOT" , SUM ( "/BIC/AZOSASALE00"."G_AVVVRM" ) AS "0G_AVVVRM" , SUM ( "/BIC/AZOSASALE00"."G_AVVWHG" ) AS "0G_AVVWHG" , SUM (
"/BIC/AZOSASALE00"."G_QABSMG" ) AS "0G_QABSMG" , SUM ( "/BIC/AZOSASALE00"."G_QVVTON" ) AS "0G_QVVTON" , SUM (
"/BIC/AZOSASALE00"."G_QVVUOM" ) AS "0G_QVVUOM" , SUM ( "/BIC/AZOSASALE00"."SALES_CMSN" ) AS "0SALES_CMSN" , SUM (
"/BIC/AZOSASALE00"."SALES_MARK" ) AS "0SALES_MARK" , COUNT( * ) AS "1ROWCOUNT"
FROM "/BI0/PDIVISION" ,"/BI0/SCO_AREA" ,"/BI0/SCURRENCY" ,"/BI0/SPROFIT_CTR" , "/BI0/SREFER_DOC" ,"/BI0/SREFER_ITM" ,"/BI0/SUNIT" "A0002" , "/BI0/SUNIT"
"A0001" ,"/BI0/SUNIT" "DB2A0001" ,"/BIC/AZOSASALE00" , "/BIC/XZMATLPLNT" ,"/BIC/XZRLNSP"
WHERE "/BIC/AZOSASALE00"."CURRENCY" = "/BI0/SCURRENCY"."CURRENCY" AND "/BIC/AZOSASALE00"."G_UVVUOM" = "A0001"."UNIT" AND
"/BIC/AZOSASALE00"."G_UABSMG" = "A0002"."UNIT" AND "/BIC/AZOSASALE00"."REFER_DOC" = "/BI0/SREFER_DOC"."REFER_DOC" AND
"/BIC/AZOSASALE00"."REFER_ITM" = "/BI0/SREFER_ITM"."REFER_ITM" AND "/BIC/AZOSASALE00"."CO_AREA" = "/BI0/SCO_AREA"."CO_AREA" AND
"/BIC/AZOSASALE00"."PROFIT_CTR" = "/BI0/SPROFIT_CTR"."PROFIT_CTR" AND "/BIC/AZOSASALE00"."CO_AREA" = "/BI0/SPROFIT_CTR"."CO_AREA" AND
"/BIC/AZOSASALE00"."/BIC/ZA_SADIV" = "/BI0/PDIVISION"."DIVISION" AND "/BIC/AZOSASALE00"."/BIC/ZMATLPLNT" = "/BIC/XZMATLPLNT"."/BIC/ZMATLPLNT" AND
"/BIC/AZOSASALE00"."PLANT" = "/BIC/XZMATLPLNT"."PLANT" AND "/BIC/AZOSASALE00"."/BIC/ZRLNSP" = "/BIC/XZRLNSP"."/BIC/ZRLNSP" AND
"/BIC/AZOSASALE00"."G_UVVTON" = "DB2A0001"."UNIT" AND "/BI0/PDIVISION"."OBJVERS" = 'A' AND "/BIC/XZMATLPLNT"."OBJVERS" = 'A' AND
"/BIC/XZRLNSP"."OBJVERS" = 'A' AND (((( "/BIC/AZOSASALE00"."ACCNT_ASGN" = '00' OR "/BIC/AZOSASALE00"."ACCNT_ASGN" = '01' OR
"/BIC/AZOSASALE00"."ACCNT_ASGN" = '04' OR "/BIC/AZOSASALE00"."ACCNT_ASGN" = '06' )) AND (( "/BIC/AZOSASALE00"."CALMONTH" BETWEEN '200311' AND
'200404' )) AND (( "/BI0/SCO_AREA"."SID" = 3 )) AND (( "/BIC/AZOSASALE00"."CURTYPE" = 'B0' )) AND (( "/BI0/SPROFIT_CTR"."SID" = 31 )) AND ((
"/BI0/PDIVISION"."/BIC/ZREPTDIV" = '5X' )) AND (( "/BIC/XZMATLPLNT"."S__ZMATLONLY" = 360013 )) AND (( "/BIC/XZRLNSP"."S__ZA_SASGRP" = 80 ))))
GROUP BY "DB2A0001"."SID" ,"/BI0/SCURRENCY"."SID" ,"A0001"."SID" ,"A0002"."SID" , "/BI0/SREFER_DOC"."SID" , "/BI0/SREFER_ITM"."SID" ) "/BI0/0300411419"
FOR FETCH ONLY WITH UR
Figure 10-1 Example customer query against an ODS
To break down a query, follow these steps:
1. Build a join graph.
204 Best Practices for SAP BI using DB2 9 for z/OS