Detect Redundant Indexes

>>Script Language and Platform: T-Sql
This script gives a table, with
Table, Index, Index contained, Index that contains.

I recommend to review each case,
before you drop.

I run it in the Query Analyzer,
one statement at a time.

Author: Fernando Madrigal Hidalgo



USE database

— tab,idx,col,order
create view listaidxcols as
select SO.name as tabname,
SI.name as idxname,
IK.keyno as keyno,
SC.name as colname
from sysindexkeys IK,
syscolumns SC,
sysindexes SI,
sysobjects SO
where — Link syscolumns
IK.id=SC.id
and IK.colid=SC.colid
— link sysindexes
and IK.id=SI.id
and IK.indid=SI.indid
— Link a sysObjects (tablas)
and IK.id=SO.id
and SO.xtype=’U’
and SI.name not like ‘_WA_Sys_%’
and SI.name not like ‘hind_%’

— how many cols x index
create view cantcolsidx
as select tabname,
idxname,
count(*) as numllaves
from listaidxcols
group by tabname,idxname

— get the redundant index list
select A.tabname as tabla,A.idxname as Aidx, B.idxname as Bidx
from cantcolsidx A, cantcolsidx B
where A.tabname = B.tabname
and A.numllaves < B.numllaves
and A.idxname <> B.idxname
and A.numllaves in (
select count(*)
from listaidxcols C, listaidxcols D
where C.tabname=A.tabname
and C.idxname=A.idxname
and D.tabname=B.tabname
and D.idxname=B.idxname
and C.idxname<>D.idxname
and C.colname=D.colname
and C.keyno =D.keyno
)

— Clean up
drop view listaidxcols;
drop view cantcolsidx;



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