Identify redundant indexes

Indexes are created to enhance performance, but often they are created with the same attributes, resulting in redundant indexes. Over a period of time the number of such indexes can grow, increasing the size of the DB2 catalog. The following SQL can help you to indentify all such indexes. It has been tested on DB2 UDB OS/390 version 7.0. 

CREATE VIEW <CREATOR>.VDUP_INDEX
(CREATOR,TBNAME,IXNAME,DUP_INDEX)
 AS                                    SELECT
 VW1.CREATOR,VW1.TBNAME,VW1.IXNAME,VW2.IXNAME
 FROM
 (SELECT
 IX.CREATOR
 AS CREATOR                                                 , IX.TBNAME
 AS TBNAME                                                  , IX.NAME
 AS IXNAME                                                  ,SUBSTR(
 MAX(CASE WHEN KY.COLSEQ = 1
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 2
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 3
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 4
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 5
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 6
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 7
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 8
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 9
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 10
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 11
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 12
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 13
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 14
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 15
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 16
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 17
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 18
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 19
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 20
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 21
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 22
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 23
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 24
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 25
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 26
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 27
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 28
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 29
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 30
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 31
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 32
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 33
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 34
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 35
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 36
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 37
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 38
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 39
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 40
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 41
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 42
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 43
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 44
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 45
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 46
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 47
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 48
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 49
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 50
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 51
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 52
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 53
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 54
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 55
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 56
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 57
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 58
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 59
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 60
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 61
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 62
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 63
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 64
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)    ,1,192)
 AS COLS
 FROM SYSIBM.SYSINDEXES  IX
 , SYSIBM.SYSKEYS     KY
 WHERE IX.CREATOR  = KY.IXCREATOR
 AND IX.NAME     = KY.IXNAME
 GROUP BY IX.CREATOR
 , IX.TBNAME
 , IX.NAME  )
 AS VW1,
 (SELECT
 IX.CREATOR
 AS CREATOR                                                 , IX.TBNAME
 AS TBNAME                                                  , IX.NAME
 AS IXNAME                                                  , SUBSTR(
 MAX(CASE WHEN KY.COLSEQ = 1
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 2
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 3
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 4
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 5
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 6
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 7
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 8
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 9
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 10
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 11
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 12
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 13
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 14
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 15
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 16
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 17
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 18
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 19
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 20
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 21
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 22
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 23
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 24
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 25
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 26
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 27
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 28
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 29
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 30
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 31
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 32
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 33
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 34
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 35
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 36
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 37
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 38
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 39
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 40
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 41
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 42
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 43
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 44
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 45
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 46
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 47
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 48
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 49
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 50
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 51
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 52
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 53
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 54
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 55
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 56
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 57
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 58
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 59
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 60
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 61
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 62
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 63
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)  ||MAX(CASE WHEN KY.COLSEQ = 64
 THEN STRIP(CHAR(KY.COLNO))||KY.ORDERING ELSE ' ' END)    ,1,192)
 AS COLS
 FROM SYSIBM.SYSINDEXES  IX
 , SYSIBM.SYSKEYS     KY
 WHERE IX.CREATOR  = KY.IXCREATOR
 AND IX.NAME     = KY.IXNAME
 GROUP BY IX.CREATOR
 , IX.TBNAME
 , IX.NAME      )
 AS VW2
 WHERE
 VW1.CREATOR=VW2.CREATOR                                             AND
 VW1.TBNAME=VW2.TBNAME                                               AND
 VW1.COLS  =VW2.COLS                                                 AND
 VW1.IXNAME<>VW2.IXNAME
Example: To get all redundant indexes on the tables with creator like %ABC%%:
Select * from <CREATOR>.VDUP_INDEX 
      where creator like '%ABC%'

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This was first published in November 2002

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