Настройка SQL - большое количество «байтов» в плане объяснения

Question

Не могли бы вы подумать о том, что может быть причиной того, что 8.2 имеет большое количество "байтов"? Заранее спасибо.

   8.2 INDEX UNIQUE SCAN S_ORG_EXT_P1 -T146208  (Cost = 1 Rows = 9390061 Bytes = 112680732 )Acc=>"A1"."ROW_ID"="A4"."PR_DEPT_OU_ID"

Полный план объяснения

 SELECT STATEMENT    Cost =37 (Cost = 37 Rows =  Bytes =  )
1.1 NESTED LOOPS     (Cost = 37 Rows = 1 Bytes = 361 )
 2.1 NESTED LOOPS     (Cost = 34 Rows = 1 Bytes = 317 )
  3.1 NESTED LOOPS     (Cost = 32 Rows = 1 Bytes = 273 )
   4.1 NESTED LOOPS     (Cost = 21 Rows = 1 Bytes = 245 )
    5.1 NESTED LOOPS     (Cost = 19 Rows = 1 Bytes = 201 )
     6.1 NESTED LOOPS     (Cost = 8 Rows = 1 Bytes = 179 )
      7.1 NESTED LOOPS     (Cost = 5 Rows = 1 Bytes = 135 )
       8.1 NESTED LOOPS     (Cost = 4 Rows = 1 Bytes = 123 )
        9.1 TABLE ACCESS BY INDEX ROWID S_OPTY -T203229  (Cost = 3 Rows = 1 Bytes = 29 ) Fil => "A4"."PR_DEPT_OU_ID" IS NOT NULL
         10.1 INDEX UNIQUE SCAN S_OPTY_P1 -T203252  (Cost = 2 Rows = 1 Bytes =  )Acc=>"A4"."ROW_ID"=:V1
        9.2 TABLE ACCESS BY INDEX ROWID S_SALES_METHOD -T134134  (Cost = 1 Rows = 327 Bytes = 30738 )
         10.1 INDEX UNIQUE SCAN S_SALES_METHOD_P1 -T143711  (Cost = 0 Rows = 1 Bytes =  )Acc=>"A5"."ROW_ID"="A4"."SALES_METHOD_ID"
       8.2 INDEX UNIQUE SCAN S_ORG_EXT_P1 -T146208  (Cost = 1 Rows = 9390061 Bytes = 112680732 )Acc=>"A1"."ROW_ID"="A4"."PR_DEPT_OU_ID"
      7.2 INDEX RANGE SCAN S_ORG_EXT_XM_BUCS1 -T246873  (Cost = 3 Rows = 1 Bytes = 44 )Acc=>"A2"."PAR_ROW_ID"="A1"."ROW_ID" AND "A2"."TYPE"='ACCOUNT_TIER' Fil => ("A2"."ATTRIB_03" IS NOT NULL AND "A2"."ATTRIB_04" IS NOT NULL)
     6.2 TABLE ACCESS BY INDEX ROWID S_POS_SKILL_IT -T133800  (Cost = 11 Rows = 10 Bytes = 220 )
      7.1 INDEX RANGE SCAN S_POS_SKILL_IT_F2 -T246871  (Cost = 2 Rows = 10 Bytes =  )Acc=>"A9"."LO_CHAR1"="A5"."NAME"
    5.2 TABLE ACCESS BY INDEX ROWID S_POS_SKILL -T133799  (Cost = 2 Rows = 1 Bytes = 44 ) Fil => "A7"."ASGN_IT_TYPE_NAME"='HPQ Opportunity Sales Method'
     6.1 INDEX UNIQUE SCAN S_POS_SKILL_P1 -T142149  (Cost = 1 Rows = 1 Bytes =  )Acc=>"A7"."ROW_ID"="A9"."POSTN_SKILL_ID"
   4.2 TABLE ACCESS BY INDEX ROWID S_POS_SKILL_IT -T133800  (Cost = 11 Rows = 1 Bytes = 28 ) Fil => ("A8"."LO_CHAR3" IS NOT NULL AND "A8"."LO_CHAR2" IS NOT NULL AND "A8"."LO_CHAR2"="A2"."ATTRIB_04")
    5.1 INDEX RANGE SCAN S_POS_SKILL_IT_F2 -T246871  (Cost = 2 Rows = 10 Bytes =  )Acc=>"A8"."LO_CHAR1"="A2"."ATTRIB_03"
  3.2 TABLE ACCESS BY INDEX ROWID S_POS_SKILL -T133799  (Cost = 2 Rows = 1 Bytes = 44 ) Fil => ("A6"."ASGN_IT_TYPE_NAME"='HPQ BU Tier BUCS' AND "A6"."POSTN_ID"="A7"."POSTN_ID")
   4.1 INDEX UNIQUE SCAN S_POS_SKILL_P1 -T142149  (Cost = 1 Rows = 1 Bytes =  )Acc=>"A6"."ROW_ID"="A8"."POSTN_SKILL_ID"
 2.2 INDEX RANGE SCAN S_ORG_EXT_XM_BUCS1 -T246873  (Cost = 3 Rows = 1 Bytes = 44 )Acc=>"A3"."PAR_ROW_ID"="A1"."ROW_ID" AND "A3"."TYPE"='BU_CUSTOMER_SEGMENT' AND "A8"."LO_CHAR3"."A3"."ATTR Fil" => ("A3"."ATTRIB_03" IS NOT NULL AND "A3"."ATTRIB_04" IS NOT NULL)

Answer 1

Он выполняет сканирование индекса по более чем 9 миллионам строк, где каждая строка занимает всего 12 байтов.

Итак, большое количество строк вызывает большое количество байтов. Если вы не хотите, чтобы он имел доступ ко всем этим данным, вам следует избегать сканирования индекса.