SAP程序性能优化

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1、ForallentriesTheforallentriescreatesawhereclause,wherealltheentriesinthedrivertablearecombinedwithOR.Ifthenumberofentriesinthedrivertableislargerthanrsdb/max_blocking_factor,severalsimilarSQLstatementsareexecutedtolimitthelengthoftheWHEREclause.Theplus

2、LargeamountofdataMixingprocessingandreadingofdataFastinternalreprocessingofdataFastTheMinusDifficulttoprogram/understandMemorycouldbecritical(useFREEorPACKAGEsize)SomestepsthatmightmakeFORALLENTRIESmoreefficient:Removingduplicatesfromthedrivertabl

3、eSortingthedrivertableIfpossible,convertthedatainthedrivertabletorangessoaBETWEENstatementisusedinsteadofandORstatement:FORALLENTRIESINi_tabWHEREmykey>=i_tab-lowandmykey<=i_tab-high.NestedselectsTheplus:oSmallamountofdataoMixingprocessingandreadingofd

4、ataoEasytocode-andunderstandTheminus:oLargeamountofdataowhenmixedprocessingisn’tneededoPerformancekillerno.1SelectusingJOINSTheplusoVerylargeamountofdataoSimilartoNestedselects-whentheaccessesareplannedbytheprogrammeroInsomecasesthefastestoNotsomemorycr

5、iticalTheminusoVerydifficulttoprogram/understandoMixingprocessingandreadingofdatanotpossibleUsetheselectioncriteriaSELECT*FROMSBOOK.CHECK:SBOOK-CARRID='LH'ANDSBOOK-CONNID='0400'.ENDSELECT.SELECT*FROMSBOOKWHERECARRID='LH'ANDCONNID='0400'.ENDSELECT.Usethe

6、aggregatedfunctionsC4A='000'.SELECT*FROMT100WHERESPRSL='D'ANDARBGB='00'.CHECK:T100-MSGNR>C4A.C4A=T100-MSGNR.ENDSELECT.SELECTMAX(MSGNR)FROMT100INTOC4AWHERESPRSL='D'ANDARBGB='00'.SelectwithviewSELECT*FROMDD01LWHEREDOMNAMELIKE'CHAR%'ANDAS4LOCAL='A'.SELECTS

7、INGLE*FROMDD01TWHEREDOMNAME=DD01L-DOMNAMEANDAS4LOCAL='A'ANDAS4VERS=DD01L-AS4VERSANDDDLANGUAGE=SY-LANGU.ENDSELECT.SELECT*FROMDD01VWHEREDOMNAMELIKE'CHAR%'ANDDDLANGUAGE=SY-LANGU.ENDSELECT.SelectwithindexsupportSELECT*FROMT100WHEREARBGB='00'ANDMSGNR='999'.E

8、NDSELECT.SELECT*FROMT002.SELECT*FROMT100WHERESPRSL=T002-SPRASANDARBGB='00'ANDMSGNR='999'.ENDSELECT.ENDSELECT.Select…IntotableREFRESHX006.SELECT*FROMT006INTOX006.APPENDX006.ENDSELECTSELECT*FROMT006INTOTABLEX006.Selectwithselection